Peptide Chemistry

The neuropeptide relaxin-3 is composed of an A chain and a B chain held together by disulfide bonds, and it modulates functions such as anxiety and food intake by binding to and activating its cognate receptor RXFP3, mainly through the B chain. Biased ligands of RXFP3 would help to determine the molecular mechanisms underlying the activation of G proteins and βarrestins downstream of RXFP3 that lead to such diverse functions. We showed that the i, i+4 stapled relaxin-3 B chains, 14s18 and d(1-7)14s18, were Gα i/o-biased agonists of RXFP3. These peptides did not induce recruitment of β-arrestin1/2 to RXFP3 by GPCR kinases (GRKs), in contrast to relaxin-3, which enabled the GRK2/3-mediated recruitment of β-arrestin1/2 to RXFP3. Relaxin-3 and the previously reported peptide 4 (an i, i+4 stapled relaxin-3 B chain) did not exhibit biased signaling. The staple linker of peptide 4 and parts of both the A chain and B chain of relaxin-3 interacted with extracellular loop 3 (ECL3) of RXFP3, moving it away from the binding pocket, suggesting that unbiased ligands promote a more open conformation of RXFP3. These findings highlight roles for the A chain and the N-terminal residues of the B chain of relaxin-3 in inducing conformational changes in RXFP3, which will help in designing selective biased ligands with improved therapeutic efficacy.

The peptide Ac-KGSFSIQYTYHVD-CONH₂ (KD), derived from residues 37-49 of human semenogelin I, forms a pH-responsive hydrogel in an aqueous environment with tunable mechanical properties that evolve over time. We hypothesize that KD self-assembles into a hydrogel through a pH-dependent mechanism involving predominantly a change in histidine protonation state, leading to structural transformations that modulate its mechanical properties. Time-resolved nuclear magnetic resonance (NMR) spectroscopy and cryo-transmission electron microscopy (cryo-TEM) were employed to elucidate the gelation process and structural evolution of KD. pH measurements were conducted to monitor changes in peptide interactions during self-assembly. Rheological studies, including oscillatory and stationary rheology, were performed to assess the mechanical properties of the hydrogel under varying pH conditions. A gradual pH drift was observed, associated with a modulation of the ionizable histidine side chain pKa as KD assembled into β-sheet fibrils, integrating into the hydrogel network. Cryo-TEM analysis revealed two distinct nanostructural morphologies: fibrils and twisted curly nanostructures with uniform dimensions, demonstrating micro-and nanoscale transformations over time. Rheological measurements indicated a substantial increase in

Cervical cancer is among the leading causes of death in women. Chemotherapy options available for cervical cancer include highly cytotoxic drugs such as taxol, cisplatin, 5-florouracil, and doxorubicin, which are not specific. In the current study, we have identified a new peptide conjugate (Fur4-2-Nal3-Ala2-Phe1-CONH2) (conjugate 4), from screening of a small library of tripeptide-conjugates of furan, as highly potent anticancer compound against human cervical cancer cells (HeLa cells) (IC50 = 0.15 ± 0.05 µg/mL or 0.28 +/− 0.09 µM). Peptides were constructed on Rink amide resin from C- to N-terminus followed by capping by α-furoic acid moiety. The synthesized peptides were purified by recycling RP-HPLC, and structures of all the peptides were confirmed by using FABMS/ESIMS, 1H- NMR, 13C-NMR, and HR-FABMS. Conjugate 4 was furthermore found to be specifically active against human cervical cancer cells since it did not inhibit the proliferation of other human normal cells (HUVEC (huma...

Photosynthetic dinoflagellates synthesize many toxic but also potential therapeutic compounds therapeutics via polyketide/non-ribosomal peptide synthesis, a common means of producing natural products in bacteria and fungi. Although canonical genes are identifiable in dinoflagellate transcriptomes, the biosynthetic pathways are obfuscated by high copy numbers and fractured synteny. This study focuses on the carrier domains that scaffold natural product synthesis (thiolation domains) and the phosphopantetheinyl transferases (PPTases) that thiolate these carriers. We replaced the thiolation domain of the indigoidine producing BpsA gene from Streptomyces lavendulae with those of three multidomain dinoflagellate transcripts and coexpressed these constructs with each of three dinoflagellate PPTases looking for specific pairings that would identify distinct pathways. Surprisingly, all three PPTases were able to activate all the thiolation domains from one transcript, although with differin...

SYNOPSIS. Separation of neuropeptides by high-pressure liquid chromatography and proteins by gel electrophoresis has been undertaken for the X-organ-sinus gland (XOSG) neurosecretory system of the crab, Cardisoma carnifex. Biosynthetic incorporation of [ 5 H]leucine by isolated XOSG systems confirms synthesis of the peptides and certain of the proteins, as well as their calcium-dependent release during secretion evoked by elevation of saline potassium. Eleven peptides (mol wt < 7,000) are consistently found in significant quantities. Characterization of these shows them to represent three groups: 1) red-pigment concentrating hormone (previously sequenced, Fernlund and Josefsson, 1972); 2) 3 hyperglycemic peptides with amino acid compositions similar to those previously reported ; and 3) 7 novel peptides whose biological activities have not been determined, labelled b, C, D, E, F, H, and I. Peptides b, C, D, E, F, and I can be explained by the partial proteolysis of peptide H at two internal sites, with non-proteolytic covalent modification of at least one of the amino-terminal fragments. Analysis of single glands shows different relative amounts of the b-I peptides in different animals, but with precise duplication of relative amounts of the b-I peptides in contralateral sinus glands. The data suggest that mixtures of peptides secreted may vary under physiological control and raise the question whether the physiological effects of such mixtures differ.

MicroRNAs (miRNAs) are a family of small noncoding RNAs that regulate gene expression. Due to their important activity in the fine-tuning of protein translation, abnormal expression of miRNAs has been linked to many human diseases, making the targeting of miRNAs attractive as a novel therapeutic strategy. Accordingly, researchers have been heavily engaged in the discovery of small molecule modulators of miRNAs. With an interest in the identification of new chemical space for targeting miRNAs, we developed a highthroughput screening (HTS) technology, catalytic enzyme-linked click chemistry assay (cat-ELCCA), aimed at the discovery of small molecule ligands for pre-miR-21, a miRNA that is frequently overexpressed in human cancers. From our HTS campaign, we found that natural products, a source of many impactful human medicines, may be a promising source of potential pre-miR-21-selective maturation inhibitors. Herein we describe our first efforts in natural product inhibitor discovery leading to the identification of a depsipeptide class of natural products as RNA-binding inhibitors of Dicer-mediated miRNA processing.

Aggregation of tau protein is a hallmark feature of tauopathies such as Alzheimer's disease. The microtubule-binding domain of tau plays a crucial role in the tau aggregation process. In this study, we investigated the dual effects of membrane interactions of tau 298-317 , a fragment peptide from the microtubule-binding domain, on peptide-induced membrane disruption and membrane-mediated peptide self-assembly. Our results show that neither wild-type tau 298-317 nor its P301L or Ser305-phosphorylated mutants aggregate in the presence of zwitterionic POPC vesicles or cause lipid vesicle leakage, indicating weak peptide-membrane interactions. In contrast, tau 298-317 strongly interacts with negatively charged POPG liposomes, leading to a rapid transition of the peptide conformation from random coils to α-helical intermediate conformation upon membrane adsorption, which may further promote peptide self-association to form oligomers and β-sheet-rich fibrillar structures. Tau 298-317-induced rapid POPG membrane leakage indicates a synergistic process of the peptide self-assembly at the membrane interface and the aggregation-induced membrane disruption. Notably, phosphorylation at Ser305 disrupts favorable electrostatic interactions between the peptide and POPG membrane surface, thus preventing peptide aggregation and membrane leakage. In contrast, the P301L mutation significantly enhances membrane-mediated peptide aggregation and peptide-induced membrane disruption, likely due to alleviation of local conformational constraints and enhancement of local hydrophobicity, which facilitates fast conformational conversion to β-sheet structures. These findings provide mechanistic insights into the molecular mechanisms underlying membrane-mediated aggregation of crucial regions of tau and peptide-induced membrane damage, indicating potential strategies to prevent tau aggregation and membrane rupture by targeting critical electrostatic interactions between membranes and key local regions of tau.

Aggregation of tau protein is a hallmark feature of tauopathies such as Alzheimer's disease. The microtubule-binding domain of tau plays a crucial role in the tau aggregation process. In this study, we investigated the dual effects of membrane interactions of tau 298-317 , a fragment peptide from the microtubule-binding domain, on peptide-induced membrane disruption and membrane-mediated peptide self-assembly. Our results show that neither wild-type tau 298-317 nor its P301L or Ser305-phosphorylated mutants aggregate in the presence of zwitterionic POPC vesicles or cause lipid vesicle leakage, indicating weak peptide-membrane interactions. In contrast, tau 298-317 strongly interacts with negatively charged POPG liposomes, leading to a rapid transition of the peptide conformation from random coils to α-helical intermediate conformation upon membrane adsorption, which may further promote peptide self-association to form oligomers and β-sheet-rich fibrillar structures. Tau 298-317-induced rapid POPG membrane leakage indicates a synergistic process of the peptide self-assembly at the membrane interface and the aggregation-induced membrane disruption. Notably, phosphorylation at Ser305 disrupts favorable electrostatic interactions between the peptide and POPG membrane surface, thus preventing peptide aggregation and membrane leakage. In contrast, the P301L mutation significantly enhances membrane-mediated peptide aggregation and peptide-induced membrane disruption, likely due to alleviation of local conformational constraints and enhancement of local hydrophobicity, which facilitates fast conformational conversion to β-sheet structures. These findings provide mechanistic insights into the molecular mechanisms underlying membrane-mediated aggregation of crucial regions of tau and peptide-induced membrane damage, indicating potential strategies to prevent tau aggregation and membrane rupture by targeting critical electrostatic interactions between membranes and key local regions of tau.

All chemicals were reagent grade, obtained from Aldrich and used without further purification, unless indicated otherwise. mPEG(2000)-NH 2 was obtained from Iris Biotech. All solvents were of analytical grade and were dried and freshly distilled. Deuterated chloroform-d1, DMSO-d6, DMF-d7 and D 2 O were purchased from Deutero GmbH. Preparative SEC was performed using Sephadex G-25 superfine from GE as well as PD MiniTrap G-10 ™ columns containing 2.1 mL of Sephadex™ G-10. Ultrafiltration was performed in a Millipore ultrafiltration device fitted with a 1, 3, or 10 KDa molecular weight cut off regenerated cellulose membrane. Characterization techniques NMR espectroscopy. 1 H and 13 C-NMR spectra were recorded on a Bruker AC 300 at room temperature and at a frequency of 300 and 75 MHz respectively and analyzed using the MestreNova 6.2 software. For SEC measurements in DMF containing 1g L -1 of lithium bromide as an additive, an Agilent 1100 series system was used with a flow rate of 1 mL min -1 at 30 °C as an integrated instrument, including three HEMA-based columns (10 5 /10 3 /10 2 Å porosity) from MZ-Analysentechnik GmbH, a UV (275 nm) and an RI detector. Calibration was achieved with well defined PEG/DMF or poly(methyl methacrylate) (PMMA)/DMF standards, provided by Polymer Standards Service (PSS)/Mainz Germany. GPC was performed with HFIP containing 3 g L -1 potassium trifuoroacetate as eluent at 40 °C. The columns were packed with modified silica (PFG columns particle size: 7 µm, porosity: 100 & 1000 Å. A refractive index detector (G 1362A RID) was used

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Komatiites represent the oldest known terrestrial rocks, and their composition has been cataloged as the closest to that of the first terrestrial crust after the cooling of the magma ocean. These rocks could have been present in multiple environments on the early Earth and served as concentrators of organic molecules. In this study, the adsorption of five amino acids (glycine, lysine, histidine, arginine, and aspartic acid) on a natural komatiite, a simulated komatiite, and the minerals olivine, pyroxene, and plagioclase were analyzed under three different pH values: acid pH (5.5), natural pH of the aqueous solution of each amino acid and alkaline pH (11). Adsorption experiments were performed in solid-liquid suspensions and organic molecules were analyzed by spectrophotometry. The main objective of this essay was to determine if the complex surfaces could have participated as concentrators of amino acids in scenarios of the primitive Earth and if the adsorption responds to the change of charge of the molecules. The results showed that komatiite is capable of adsorbing amino acids in different amounts depending on the experimental conditions. In total, 75 systems were analyzed that show different adsorptions, which implies that different interactions are involved, particularly in relation to the type of amino acid, the type of solid material and the conditions of the medium.

Understanding the effect that specific amino acids (AA) exert on calcium phosphate (CaPs) formation is proposed as a way of providing deeper insight into CaPs' biomineralization and enabling the design of tailored-made additives for the synthesis of functional materials. Despite a number of investigations, the role of specific AA is still unclear, mostly because markedly different experimental conditions have been employed in different studies. The aim of this paper was to compare the influence of different classes of amino acids, charged (aspartic acid, Asp and lysine, Lys), polar (asparagine, Asn and serine, Ser) and non-polar (phenylalanine, Phe) on CaPs formation and transformation in conditions similar to physiological conditions. The precipitation process was followed potentiometrically, while Fourier transform infrared spectroscopy, powder X-ray diffraction, electron paramagnetic spectroscopy (EPR), scanning and transmission electron microscopy were used for the characterization of precipitates. Except for Phe, all investigated AAs inhibited amorphous calcium phosphate (ACP) transformation, with Ser being the most efficient inhibitor. In all systems, ACP transformed in calcium-deficient hydroxyapatite (CaDHA). However, the size of crystalline domains was affected, as well as CaDHA morphology. In EPR spectra, the contribution of different radical species with different proportions in diverse surroundings, depending on the type of AA present, was observed. The obtained results are of interest for the preparation of functionalized CaPs', as well as for the understanding of their formation in vivo.

Understanding the effect that specific amino acids (AA) exert on calcium phosphate (CaPs) formation is proposed as a way of providing deeper insight into CaPs’ biomineralization and enabling the design of tailored-made additives for the synthesis of functional materials. Despite a number of investigations, the role of specific AA is still unclear, mostly because markedly different experimental conditions have been employed in different studies. The aim of this paper was to compare the influence of different classes of amino acids, charged (aspartic acid, Asp and lysine, Lys), polar (asparagine, Asn and serine, Ser) and non-polar (phenylalanine, Phe) on CaPs formation and transformation in conditions similar to physiological conditions. The precipitation process was followed potentiometrically, while Fourier transform infrared spectroscopy, powder X-ray diffraction, electron paramagnetic spectroscopy (EPR), scanning and transmission electron microscopy were used for the characterizat...

Thymosin β4 (Tβ4) was extracted forty years ago 1 from calf thymus. Since then, it has been identified as a G-actin binding protein involved in blood clothing, tissue regeneration, angiogenesis, and anti-inflammatory processes. Tβ4 has also been implicated in tumor metastasis and neurodegeneration. However, the precise roles and mechanism(s) of action of Tβ4 in these processes remain largely unknown, with the binding of the G-actin protein being insufficient to explain these multi-actions. Here we identify for the first time the important part of Tβ4 mechanism in ferroptosis, an iron-dependent form of cell death, which leads to neurodegeneration and somehow protects cancer cells against cell death. Specifically, we demonstrate four iron2+and iron3+ binding regions along the peptide and show that the presence of Tβ4 in cell growing medium inhibits erastin and glutamate-induced ferroptosis in macrophage cell line. Moreover, Tβ4 increases the expression of oxidative stress-related gene...

Context: SARS-CoV-2, a member of family Coronaviridae and the causative agent of COVID-19, is a virus which is transmitted to human and other mammals. Aims: To analyze the B-cell epitope conserved region and viroinformatics-based study of the SARS-CoV-2 lineage from Indonesian B.1.1.7 isolates to invent a vaccine nominee for overcoming COVID-19. Methods: The sequences of seven Indonesian B.1.1.7 isolates, Wuhan-Hu-1 isolate, and WIV04 isolate were extracted from the GISAID EpiCoV and GenBank, NCBI. MEGA X was employed to understand the transformations of amino acid in the S protein and to develop a molecular phylogenetic tree. The IEDB was implemented to reveal the linear B-cell epitopes. In addition, PEP-FOLD3 web server was utilized to perform peptide modeling, while docking was performed using PatchDock, FireDock, and the PyMOL software. Moreover, in silico cloning was developed by using SnapGene v.3.2.1 software. Results: In this study, the changes of amino acid in all seven Ind...

Peptide ligation and macrocyclization are among the most relevant approaches in the field of peptide chemistry. Whereas a variety of strategies relying on coupling reagents and native chemical ligation are available, there is a continuous need for efficient peptide ligation and cyclization methods. Herein we report on the utilization of convertible isonitriles as effective synthetic tools for the ligation and macrocyclization of peptides arising from isocyanide-based multicomponent reactions. The strategy relies on the use of convertible isonitriles - derived from Fukuyama amines - and peptide carboxylic acids in Ugi and Passerini reactions to afford N-alkylated peptides and depsipeptides, respectively, followed by conversion of the C-terminal amide onto either N-peptidoacyl indoles or pyrroles. Such activated peptides proved efficient in the ligation to peptidic, lipidic and fluorescently labeled amines and in macrocyclization protocols. As a result, a wide set of N-substituted pep...

Context: SARS-CoV-2, a member of family Coronaviridae and the causative agent of COVID-19, is a virus which is transmitted to human and other mammals. Aims: To analyze the B-cell epitope conserved region and viroinformatics-based study of the SARS-CoV-2 lineage from Indonesian B.1.1.7 isolates to invent a vaccine nominee for overcoming COVID-19. Methods: The sequences of seven Indonesian B.1.1.7 isolates, Wuhan-Hu-1 isolate, and WIV04 isolate were extracted from the GISAID EpiCoV and GenBank, NCBI. MEGA X was employed to understand the transformations of amino acid in the S protein and to develop a molecular phylogenetic tree. The IEDB was implemented to reveal the linear B-cell epitopes. In addition, PEP-FOLD3 web server was utilized to perform peptide modeling, while docking was performed using PatchDock, FireDock, and the PyMOL software. Moreover, in silico cloning was developed by using SnapGene v.3.2.1 software. Results: In this study, the changes of amino acid in all seven Ind...

The effect of Cu 2+ on α-synuclein (AS) aggregation is important because clinical studies of patients with Parkinson's disease have shown elevated levels of Cu 2+ in the cerebrospinal fluid. So far, the molecular architectures of Cu 2+ -AS fibril complexes at atomic resolution are unknown. The current work identifies for the first time that His50 cannot bind Cu 2+ ions in mature fibrils. Moreover, it shows hopping of Cu 2+ ions between residues in AS fibrils and changes in the Cu 2+ coordination mode in Cu 2+ ions that bind in the termini of AS. The current study combines extensive experimental techniques, density functional theory calculations, and computational modeling tools to provide a complete description of the Cu 2+ binding site in AS fibrils. Our findings illustrate for the first time the specific interactions between Cu 2+ ions and AS fibrils, suggesting a new mechanistic perspective on the effect of Cu 2+ ions on AS aggregation.

A peptide corresponding to a 13-residue segment of the human protein semenogelin I has been shown to generate a hydrogel consisting of amyloid-like fibrils. The relative chemical diversity (compared to synthetic de novo sequences) with 11 distinct amino acids makes this peptide (P0) an ideal candidate for investigating the role of individual residues in gelation. Herein, the N-terminal residues have been sequentially removed to furnish a series of truncated peptides, P1-P10, ranging from 12 to 3 residues in length. FTIR spectroscopy investigations reveal that P0-P6 forms a β-sheet secondary structure while shorter sequences do not selfassemble. Site-specific isotope labeling of the amide backbone of P0-P2 with the IR-sensitive vibrational probe 13 C�O yields FTIR spectra indicative of the initial formation of a kinetic product that slowly transforms into a structurally different thermodynamic product. The effects of the isotopic labels on the IR spectra facilitate the assignment of parallel and antiparallel structures, which are sometimes coexistent. Additional IR studies of three Phe CN-labeled P0 sequences are consistent with an H-bonded β-sheet amide core, spanning the 7 central residues. The macromolecular assembly of peptides that form β-sheets was assessed by cryo-TEM, SAXS/WAXS, and rheology. Cryo-TEM images of peptides P1-P6 display μm-long nanofibrils. Peptides P0-P3 generate homogeneous hydrogels composed of colloidally stable nanofibrils, and P4-P6 undergo phase separation due to the accumulation of attractive interfibrillar interactions. Three amino acid residues, Ser39, Phe40, and Gln43, were identified to be of particular interest in the truncated peptide series as the removal of any one of them, as the sequence shortens, leads to a major change in material properties.

In the past two decades, the number of hedge funds and the amount of assets being managed by hedge funds have skyrocketed in lockstep with increased allocations to hedge funds from institutional investors across the globe. This paper discusses the importance of manager selection in the hedge fund allocation process. It then touches on the development of the Capital Asset Pricing Model, a pivotal time in the history of fund performance measurement. Finally, it explores how a portfolio manager uses quantitative metrics in practice to evaluate potential hedge fund investment opportunities illustrated with an example of manager selection by an existing institutional investment portfolio manager.

The neuroleptic drug thioridazine has been recently repositioned as possible anti-tubercular drug. Thioridazine showed anti-tubercular activity against drug resistant mycobacteria but it is endowed with adverse side effects. A small library of thioridazine derivatives has been designed through the replacement of the piperidine and phenothiazine moieties, with the aim to improve the anti-tubercular activity and to reduce the cytotoxic effects. Among the resulting compounds, the indole derivative 12e showed an antimycobacterial activity significantly better than thioridazine and a cytotoxicity 15-fold lower.

Short cyclic peptides have a great interest in therapeutic, diagnostic and affinity chromatography applications. The screening of 'one-bead-one-peptide' combinatorial libraries combined with mass spectrometry (MS) is an excellent tool to find peptides with affinity for any target protein. The fragmentation patterns of cyclic peptides are quite more complex than those of their linear counterparts, and the elucidation of the resulting tandem mass spectra is rather more difficult. Here, we propose a simple protocol for combinatorial cyclic libraries synthesis and ring opening before MS analysis. In this strategy, 4hydroxymethylbenzoic acid, which forms a benzyl ester with the first amino acid, was used as the linker. A glycolamidic ester group was incorporated after the combinatorial positions by adding glycolic acid. The library synthesis protocol consisted in the following: (i) incorporation of Fmoc-Asp[2-phenylisopropyl (OPp)]-OH to Ala-Gly-oxymethylbenzamide-ChemMatrix, (ii) synthesis of the combinatorial library, (iii) assembly of a glycolic acid, (iv) couple of an Ala residue in the N-terminal, (v) removal of OPp, (vi) peptide cyclisation through side chain Asp and N-Ala amino terminus and (vii) removal of side chain protecting groups. In order to simultaneously open the ring and release each peptide, benzyl and glycolamidic esters were cleaved with ammonia. Peptide sequences could be deduced from the tandem mass spectra of each single bead evaluated. The strategy herein proposed is suitable for the preparation of one-bead-one-cyclic depsipeptide libraries that can be easily open for its sequencing by matrix-assisted laser desorption/ionisation MS. It employs techniques and reagents frequently used in a broad range of laboratories without special expertise in organic synthesis.

Short cyclic peptides have a great interest in therapeutic, diagnostic and affinity chromatography applications. The screening of 'one-bead-one-peptide' combinatorial libraries combined with mass spectrometry (MS) is an excellent tool to find peptides with affinity for any target protein. The fragmentation patterns of cyclic peptides are quite more complex than those of their linear counterparts, and the elucidation of the resulting tandem mass spectra is rather more difficult. Here, we propose a simple protocol for combinatorial cyclic libraries synthesis and ring opening before MS analysis. In this strategy, 4hydroxymethylbenzoic acid, which forms a benzyl ester with the first amino acid, was used as the linker. A glycolamidic ester group was incorporated after the combinatorial positions by adding glycolic acid. The library synthesis protocol consisted in the following: (i) incorporation of Fmoc-Asp[2-phenylisopropyl (OPp)]-OH to Ala-Gly-oxymethylbenzamide-ChemMatrix, (ii) synthesis of the combinatorial library, (iii) assembly of a glycolic acid, (iv) couple of an Ala residue in the N-terminal, (v) removal of OPp, (vi) peptide cyclisation through side chain Asp and N-Ala amino terminus and (vii) removal of side chain protecting groups. In order to simultaneously open the ring and release each peptide, benzyl and glycolamidic esters were cleaved with ammonia. Peptide sequences could be deduced from the tandem mass spectra of each single bead evaluated. The strategy herein proposed is suitable for the preparation of one-bead-one-cyclic depsipeptide libraries that can be easily open for its sequencing by matrix-assisted laser desorption/ionisation MS. It employs techniques and reagents frequently used in a broad range of laboratories without special expertise in organic synthesis.

Our objective is to investigate the smaller chain tripeptides and tetrapeptides with the efforts mainly directed towards the identifi cation
of compounds presenting a high bactericidal activity. In this connection, 5 peptides, Met- Arg-Tyr (MRY), Met-Val-Tyr (MVY), Met-Ile-Cys-Tyr (MICY), Phe-Trp-Lys-Tyr (FWKY) and Met-Trp-Lys-Tyr (MWKY)  were synthesized by
solid phase peptide synthesis. The column eluted pure synthesized compounds were tested for in-vitro antibacterial disc diff usion assay using 2 g positive S. aureus , B.subtilis and 1 g negative E.coli bacterial strains at different concentrations predicted by pH and inhibitory concentration fi dings. 2 of the tetrapeptides, Phe-Trp-Lys-
Tyr (FWKY) and Met-Trp-Lys-Tyr (MWKY) were
found to be highly effi cient against all the gram
positive and microbial strains tested. Maximum
activity was observed at a concentration
of 300 μg/ml (499.17 μM) for the tetrapeptide
Phe-Trp-Lys-Tyr (FWKY) against B. subtilis and
at a concentration of 450 μg/ml (748.75 μM)
against E. coli with the corresponding zonal
inhibition diameter readings (17 mm; 16 mm).
The tetrapeptide Met-Trp-Lys-Tyr (MWKY) was
found to have high potency against S. aureus at
a concentration of 450 μg/ml (769.23 μM) with
the corresponding zonal inhibition diameter as
13 mm. The experimental results are analysed
statistically by t-test at 5 % and 1 % level of signifi
cance. Our tetrapeptides have shown antibacterial
action against both gram positive and
gram negative strains and are considered safer as
par with commercial antibiotics available today.
Further clinical studies will make sure to position
our potent small chain tetrapeptides in the
arsenal of new broad spectrum anti-gram positive and anti-gram negative agent

Eyestalk ablation is a procedure that involves removing one or both of a shrimp's eyes to encourage faster reproduction. It's performed in aquaculture and hatchery operations for commercially important shrimp species. Attempts at bilateral eyestalk ablation (both eyes) were made by French researchers in the early 1970s to assess the stimulating effect of ablation on the reproduction of decapod crustaceans for Penaeid culture. Unilateral eyestalk ablation, which produced a modest hormonal stimulation without ova reabsorption or increased mortality, helped solve these problems. As a result, unilateral eyestalk ablation gained popularity all around the world as an easy way of getting several species of Penaeid shrimp raised in captivity to reproduce.

Resumen Se realizó la síntesis de un péptido quimérico de 82 residuos derivado de cuatro proteínas del Plasmodium falciparum mediante la metodología de síntesis de péptidos en fase sólida (SPFS) utilizando química Fmoc y se evaluó tres estrategias sintéticas para optimizar la síntesis de este. Dos de las variaciones sintéticas realizadas presentaron un aumento moderado en la eficiencia sintética de esta quimera peptídica. Además, se evaluó la actividad biológica de este péptido. Inicialmente, se evaluó el efecto del calentamiento asistido por radiación microondas a la síntesis encontrando que el principal efecto del calentamiento fue la reducción de los tiempos de síntesis y la disminución de los acoples empleados para la formación del péptido quimérico, además, del aumento del rendimiento; se prosiguió a evaluar sustituciones de resina menores (0.15 meq/g, 0.10 meq/g y 0.08 meq/g) a la inicialmente evaluada de 0.20 meq/g para determinar si estas tenían un efecto positivo en la sínt...

ABSTRACTValley fever (VF) is difficult to diagnose, partly because the symptoms of VF are confounded with those of other community-acquired pneumonias. Confirmatory diagnostics detect IgM and IgG antibodies against coccidioidal antigens via immunodiffusion (ID). The false-negative rate can be as high as 50% to 70%, with 5% of symptomatic patients never showing detectable antibody levels. In this study, we tested whether the immunosignature diagnostic can resolve VF false negatives. An immunosignature is the pattern of antibody binding to random-sequence peptides on a peptide microarray. A 10,000-peptide microarray was first used to determine whether valley fever patients can be distinguished from 3 other cohorts with similar infections. After determining the VF-specific peptides, a small 96-peptide diagnostic array was created and tested. The performances of the 10,000-peptide array and the 96-peptide diagnostic array were compared to that of the ID diagnostic standard. The 10,000-p...

Aggregation of amino acids to amyloid like structures is known to have implications in the pathophysiology of single amino acids based inborn-errors of metabolism (IEMs). Studying the aggregation properties of amino acids is of crucial interest also to understand the association of these IEMs to amyloid associated diseases. Hence, herein we have studied the self-assembly of different non-aromatic charged/uncharged polar amino acids namely L-Glutamine (Gln), L-Aspartic acid (Asp), L-Glutamic acid (Glu) L-Histidine (His), L-Arginine (Arg), L-Serine (Ser) and L-Threonine (Thr) whose amyloid characteristics have still not been explored by ageing them for varying time intervals from 0-15 days in aqueous solution. The structure formation by the self-assembly of these amino acids were then studies by microscopy., Notably, of all amino acids glutamine revealed amyloid like febrile morphologies as observed in case of aromatic amino acids. The MTT assay also revealed a relatively more cytotox...

The identification of MHC binding peptides for consideration as potential T-cell epitopes has application in peptide vaccine design and immunotherapy. Determination of MHCp binding using experimental measures is time-consuming and expensive. Therefore, efficient prediction models are required that facilitate systematic computational scanning of microbial genome for candidate T cell epitopes. These prediction models are either sequence or 3D structure based. This review provides a comparative analysis on the available prediction models with specific emphasis on the salient features of each model, its prediction efficiency, and merits and demerits.

Scheme S1. Reaction sequence for the synthesis of cyclic D,L-α-peptide libraries. Reaction and conditions: i. DIPEA in CH 2 Cl 2 , ii. 20% Piperidin in DMF, iii. Fmoc-AA n -OH, DIC/HOBT in NMP, iv. repeats of step ii and iii, v. Hydrazine hydrate in DMF, vi. PyBOP/HOAT/DIPEA, 3h vii. TFA/H 2 O/triisopropylsilane (95/2.5/2.5), 2h.

Six GIP 1-30NH2 analogs were synthesized with modifications (de-protonation, N-methylation, reversed chirality, and substitution) at positions 1, 3, and 4 of the N-terminus, and additionally, a cyclized GIP derivative was synthesized. The relationship between altered structure to biological activity was assessed by measuring receptor binding affinity and ability to stimulate adenylyl cyclase in CHO-K1 cells transfected with the wild-type GIP receptor (wtGIPR). These structure-activity relationship studies demonstrate the importance of the GIP N-terminus and highlight structural constraints that can be introduced in GIP analogs. These analogs may be useful starting points for design of peptides with enhanced in vivo bioactivity.

The “Method of treating late-onset congenital adrenal hyperplasia due to 21-hydroxylase deficiency by individually tailored glucocorticoid regimen” is the invention in the domain of medical science, namely, endocrinology, and can be practically used to treat adult humans who suffer from symptoms of late-onset 21-hydroxylase deficiency caused by the mutation of the CYP21A2 gene. The method consists of daily intake of two glucocorticoids: dexamethasone in evenings and hydrocortisone in the mornings, in doses specially selected for each patient based on the analysis and monitoring of 17α-hydroxyprogesterone, progesterone, sex hormone-binding globulin, adrenocorticotropic hormone, fasting glucose, hemoglobin A1C, C-Peptide, the Parathyroid Hormone intact, blood pressure, body weight. During glucocorticoid intake, in order to counterbalance adverse reactions, the patient should also take supplements of potassium, calcium, vitamin D and vitamin K. The result is a cheap, effective and safe treatment of the symptoms of the mentioned disease.

The cholecystokinin-2 receptor (CCK2R) is a G protein-coupled receptor (GPCR) that is expressed in peripheral tissues and the central nervous system and constitutes a promising target for drug development in several diseases, such as gastrointestinal cancer. The search for ligands of this receptor over the past years mainly resulted in the discovery of a set of distinct synthetic small molecule chemicals. Here, we carried out a pharmacological screening of cyclotide-containing plant extracts using HEK293 cells transiently-expressing mouse CCK2R, and inositol phosphate (IP1) production as a readout. Our data demonstrated that cyclotide-enriched plant extracts from Oldenlandia affinis, Viola tricolor and Carapichea ipecacuanha activate the CCK2R as measured by the production of IP1. These findings prompted the isolation of a representative cyclotide, namely caripe 11 from C. ipecacuanha for detailed pharmacological analysis. Caripe 11 is a partial agonist of the CCK2R (Emax = 71%) wit...

Complexes of Cu(lysine) 2+ and Cu(histidine) 2+ have been intercalated between the layers of saponite clays by a simple cation exchange procedure from aqueous solutions of preformed Cu(amino acid)2-complexes. Successful immobilization was obtained with an amino acid:Cu 2 § ratio of 5, and a pH of 10 and 7.3 for lysine and histidine, respectively. The synthesized materials were investigated as powders and as thin films by electron spin resonance (ESR), diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD). The light blue clays are characterized by an axially symmetric ESR spectrum with A//= 192 G, g//= 2.23 and g• = 2.07, and a d-d absorption band around 600 nm, due to the intercalated planar Cu2*-complexes. Ammonia interacts reversibly with these intercalated complexes, suggesting the presence of a free coordination site. The novel synthesized materials are active in various oxidation reactions with t-butyl hydroperoxide as oxidant.

The spectroscopic properties and catalytic behavior of Cu(AA) n m+ complexes (AA) amino acid (glycine, lysine, histidine, alanine, serine, proline, tyrosine, phenylalanine, glutamine, glutamic acid, cysteine, tryptophan, leucine, and arginine)) in faujasite-type zeolites have been investigated. Successful immobilization was achieved by a simple cation exchange procedure with aqueous solutions of preformed Cu(AA) n m+ complexes. The best ion exchange results were obtained with lysine, arginine, proline (at pH) 10), and histidine (at pH) 7.3) as ligands and with a AA:Cu 2+ ratio of 5. The internal surface and pore volume are drastically reduced by the uptake of the Cu(AA) n m+ complexes, and no precipitation of Cu(AA) n m+ crystals was observed by scanning electron microscopy. Both observations suggest the location of the complexes in the supercages of the faujasite-type zeolites. The composition of the first coordination sphere around Cu 2+ can be designed from NNNN to NOOO by varying the type of amino acid. A free coordination site is available for catalysis, and the oxidation of alcohols, alkanes, and alkenes with peroxides was observed at low temperatures.

The spectroscopic properties and catalytic behavior of Cu(AA) n m+ complexes (AA) amino acid (glycine, lysine, histidine, alanine, serine, proline, tyrosine, phenylalanine, glutamine, glutamic acid, cysteine, tryptophan, leucine, and arginine)) in faujasite-type zeolites have been investigated. Successful immobilization was achieved by a simple cation exchange procedure with aqueous solutions of preformed Cu(AA) n m+ complexes. The best ion exchange results were obtained with lysine, arginine, proline (at pH) 10), and histidine (at pH) 7.3) as ligands and with a AA:Cu 2+ ratio of 5. The internal surface and pore volume are drastically reduced by the uptake of the Cu(AA) n m+ complexes, and no precipitation of Cu(AA) n m+ crystals was observed by scanning electron microscopy. Both observations suggest the location of the complexes in the supercages of the faujasite-type zeolites. The composition of the first coordination sphere around Cu 2+ can be designed from NNNN to NOOO by varying the type of amino acid. A free coordination site is available for catalysis, and the oxidation of alcohols, alkanes, and alkenes with peroxides was observed at low temperatures.

NMR investigations of model protein of elastic fibre is presented. Detailed conformation of alpha-elastin polypeptide chain is discussed by comparison with the conformation of synthetic repeat peptides of elastin. Amino acid composition of alpha-elastin obtained from C-13 NMR spectra correlates with the results of sequencing of tropoelastin.

We have studied the ability of human C-reactive protein to modulate the immune response in vitro. Whereas native C-reactive protein did not induce phagocytic leukocytes to chemotax or to produce superoxide, treatment of purified C-reactive protein with human neutrophil-derived acid proteases produced substances with potent effects on leukocyte function. Close examination of the primary structure of human C-reactive protein revealed three regions evenly distributed throughout the protein each of which contain peptide sequences closely resembling the amino acid sequence of the immunomodulator peptide tuftsin, Thr-Lys-Pro-Arg. We have synthesized the three peptides which include Thr-Lys-Pro-Leu ([Leu'ltuftsin), Gly-Lys-Pro-Arg ([Gly'ltuftsin), and Thr-Lys-Pro-Gln ([Gln4]tuftsin) and assayed them for biological activity. The three synthetic peptides were found to stimulate phagocytic leukocytes to chemotax, produce superoxide, and induce mononuclear cells to produce interleukin 1 in vitro at concentrations similar to those concentrations required for tuftsin to induce these phenomena. These results support a potentially important role for C-reactive protein as a possible immunomodulator during inflammation.

Several side reactions have been detected for cysteine-containing peptides. During the synthesis of C-terminal cysteine peptides, a base-catalyzed elimination of the sulfhydryl-protected side-chain to afford the dehydroalanine derivative followed by a nucleophilic addition to the alkene was observed. MALDI-TOF analysis was a useful analytical technique to determine this phenomenon.