Download or read book Development of New Approaches for the Synthesis and Decoding of One bead One compound Cyclic Peptide Libraries written by Xinxia Liang and published by . This book was released on 2016 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: A great number of cellular and biological processes depend, at some level, on protein-protein interactions (PPI). Their manipulation with chemical compounds has provided a great potential for the discovery of new drugs. Despite the increasing demand for molecules able to interrupt specific PPI, the development of small PPI inhibitors is beset by a number of challenges such as the large size of the interaction interface. Based on the interface's nature, the ability to mimic protein secondary structures is very important to bind a protein and inhibit PPI. With their interesting peptidomimetic abilities and pharmacological properties, cyclic peptides are very promising templates to discover protein ligands and development new PPI inhibitors. To fully exploit the great diversity accessible with cyclic peptides, the one-bead-one-compound (OBOC) combinatorial method is certainly the most accessible and powerful approach. Unfortunately, the use of cyclic peptides in OBOC libraries is limited by difficulties in sequencing hit compounds after the screening. Lacking a free N-terminal amine, Edman degradation cannot be used on cyclic peptides and complicated fragmentation patterns are obtained by tandem mass spectrometry (MS/MS). In this regard we have designed and developed new convenient ring-opening approaches to prepare and decode OBOC cyclic peptide libraries. Our strategy was to introduce a cleavable residue in the macrocycle and as a linker to allow linearization of peptides and their release from the beads for sequencing by MS/MS. First, amino acid residues sensible to nucleophiles, ultraviolet irradiation or cyanogens bromide were introduced in a model cyclic peptide. Afterward, the most promising residues were used to design and develop tandem ring-opening/cleavage approaches to decode OBOC cyclic peptide libraries. In the first approach a methionine residue was introduced in the macrocycle and as a linker to allow a simultaneous ring-opening and cleavage from the beads upon treatment with cyanogens bromide. In the second approach, a photosensitive residue was used in the macrocycle and as a linker for a dual ring-opening/cleavage upon UV irradiation. The linear peptide generated by these approaches can be efficiently sequenced by tandem mass spectrometry. Finally, an OBOC library has been prepared and screened against the HIV-1 Nef protein to identify selective ligands. The development of these methodologies will prompt the use of macrocyclic compounds in OBOC libraries and be an important contribution in medicinal chemistry for the discovery of protein ligands and the development of PPI inhibitors.
Download or read book Exploration of the Applications of One bead One compound Combinatorial Libraries in Probe Development and Drug Discovery written by Shabnam Jafari and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The one-bead one-compound (OBOC) concept was first recognized by Lam et al. in 1991 in application of identifying small linear peptides that bind to anti-[beta]-endorphin antibody and streptavidin.1 This concept is based on the fact that combinatorial bead libraries, prepared via a "split synthesis" approach, contain single beads displaying only one type of compound although there may be up to 1013 copies of the same compound on a single 90-100 [mu]m diameter bead. OBOC libraries are not limited to linear peptides. This technique covers synthesis of libraries of cyclic peptides, peptoids, peptidomimetics, small molecules, etc. The technique further expanded from on-bead screening to in situ releasable assays, in which the portion of library compound are released from each bead in solution.2 The use of high-density microbead cassettes allowed both in situ releasable solution phase assays and efficient bead mobilization. The sequence of the peptides comprised of [alpha]-amino acids and have a free N-terminus can be identified by Edman chemistry. For peptides that are not sequenceable by Edman microsequencing technique, a biphasic approach was invented to generate topologically segregated bilayer beads with library compounds on the outer layer of each bead and the coding tags inside each bead.4 Over the last three decades, OBOC method has evolved tremendously, in the areas of solid-support, chemical encoding, synthetic chemistry, and high-throughput biochemical and cell-based screening. This thesis focuses on the various applications of OBOC illustrated by three different projects, each is explained in one chapter. Chapter 1 discusses the use of OBOC method for rapid discovery of illuminating peptides for instant detection of opioids in blood. Current approaches for opioid identification and quantification in body fluids include immunoassays and chromatographic methods (e.g., LC-MS, GC-MS) that require expensive instrumentation and extensive sample preparation. In this chapter we report the development of a portable morphine-sensitive fluorescence-based sensor chip to sensitively detect morphine in blood using a homogenous immunoassay without any washing steps. Morphine-sensitive illuminating peptides were identified by a high throughput OBOC combinatorial peptide library approach. The OBOC libraries contain a large number of random peptides with a molecular rotor dye, malachite green (MG), coupled to the amino group on the side chain of lysine at different positions of the peptides. The OBOC libraries were then screened for fluorescence activation under a laser scanning confocal microscope, using an anti-morphine monoclonal antibody as the screening probe, in the presence and absence of free morphine. Using this novel three-step fluorescent screening assay, we were able to identify peptide-beads that fluoresced in the presence of anti-morphine antibody, but lost fluorescence when free morphine was present. After positive beads were decoded using automatic Edman microsequencing, the morphine-sensitive illuminating peptides were synthesized in soluble form, functionalized with an azido group, and immobilized onto microfabricated PEG-array spots on a glass slide. This proof-of-concept platform can be used to develop fluorescence-based sensors against morphine. More importantly, this technology can also be applied to the discovery of other novel illuminating peptidic sensors for detection of illicit drugs and cancer biomarkers in body fluids. Chapter 2 discusses the use of OBOC method to discover short peptide-dye pairs that can be genetically fused to target integral membrane proteins (IMPs) and used as genetically encoded small illuminants (GESIs) for functional cellular imaging. In this chapter, we establish a methodology to create a toolbox of functional illuminants to tag cellular proteins and probe the spatiotemporal dynamics, activation and phosphorylation of these proteins in living cells. This method relies on the OBOC technology coupled with confocal microscopy to screen and identify short peptide(s) that activate fluorophores which can be used as GESIs for functional cellular imaging. As opposed to large protein-based fluorophores (e.g., green fluorescent protein, or GFP), these GESIs are small (~2kDa), allowing them to be readily inserted along the sequence of IMPs without interfering with their physiological functions. This research will assist in broadening the field of fluorescence-based molecular imaging, both in vitro and in vivo. As a proof of concept, we have genetically inserted our GESIs between GFP and the transmembrane domain of PDGFR, such that the resulting GFP-GESI fusion would be expressed and displayed on the surface of HEK293 cells. We then used bromocresol purple to demonstrate the utility of the proposed genetically encoded functional imaging system to probe model intrinsic membrane protein in living cells. Chapter 3 describes a novel approach to minimize non-specific binding of target protein during OBOC combinatorial library screening while identifying strong thrombin inhibitors with potential clinical use as anticoagulants. In this chapter, we assessed the viability of various linkers, resins, and percentage of the resin surface containing peptides to develop a robust screening method for OBOC libraries, such that non-specific binding and false-positive results can be minimized. Using bivalirudin, an FDA-approved anticoagulant as a model, we were able to develop a linker, resin and peptide composition combination that minimized non-specific binding as shown via gel electrophoresis. As a proof of concept, an OBOC library was subsequently designed incorporating these parameters and screened against thrombin which led to discovery of six hits. All the six peptides were then proved to be true positives. We were able to demonstrate that lowering the concentration of hit compound density on the surface of beads to 50% and coating the remaining 50% of the surface with stealth hexapeptide (EK)3 as a way to greatly eliminate nonspecific binding, thus maximizing the chance of true-positive bead identification. In addition, the positive sequences found through OBOC screening with thrombin, would be of interest as they may yield clinically useful anticoagulants.
Download or read book Development of Cyclic Peptidyl Ligands Through a Combinatorial Library Approach written by Tao Liu and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Cyclic peptides are widely produced in nature and possess a broad range of biological activities. Their enhanced proteolytic stability in vivo and improved receptor binding affinity/specificity makes them excellent drug candidates, molecular probes and targeting agents. In fact, many cyclic peptides are clinically used therapeutic agents. Combinatorial library approaches provide powerful tools for the rapid identification of compounds with desired properties from large pools in biological and biomedical studies. However, the synthesis and screening of cyclic peptide libraries in a combinatorial format has been challenging. To overcome the issue, we have successfully developed one-bead-two-compound (OBTC) libraries with a cyclic peptide displayed on the bead surface accessible for protein targets screening, while the bead interior contains the corresponding linear peptide served as an encoding tag for hit identification. The primary goal of my research is to identify novel biologically active cyclic peptides, beyond what nature has provided us. By applying cyclic peptide library approach, we have successfully identified high affinity ligands against various biological targets, including: extracellular protein receptors (human prolactin receptor), intracellular protein domains (the capsid domain of HIV-1 Gag polyprotein and calcineurin catalytic domain) and enzymes (Pin1 catalytic domains). In the meantime, we have continued to improve the methodologies associated with combinatorial chemistry. To facilitate the process and improve the screening results, such as avoiding false positives, we have developed many cyclic library approaches including libraries on different solid supports, reduced surface density libraries, high diversity libraries with different ring sizes and library compatible with rapid solution phase validation. These new approaches greatly facilitate the ligands discovery process. My final work focused on the intracellular delivery of cyclic peptides. Little is known about how cyclization would affect peptides membrane permeability and the results from existing studies are controversial. With a combination of biophysical approaches and cell based studies, we have found that cyclization has a dramatic effect on the cell permeation of peptides with certain residues. By applying the rules, we were able to design cell permeable cyclic peptide inhibitors against various intracellular protein targets. Our studies provide guiding principles for designing membrane penetrating cyclic peptidyl drugs.
Download or read book Synthesis and Screening of Support bound Combinatorial Cyclic Peptide and Free C terminal Peptide Libraries written by Sang Hoon Joo and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: One-bead one-compound (OBOC) peptide libraries have been useful tools in the biomedical sciences. However, OBOC peptide libraries usually display the N-termini of peptides on the surface as conventional solid phase peptide synthesis proceeds in the C to N direction. While large combinatorial libraries of cyclic peptides can be synthesized by the split-and-pool synthesis method, the sequence determination has been a challenge. Also, peptide libraries with free C-termini face the same problem as well as the difficulty of synthesis in the N to C direction. We report here the development of cyclic peptide libraries and C-terminal peptide libraries for high-throughput screening and sequencing. TentaGel microbeads (90 um) were spatially segregated into outer and inner layers; cyclic peptides were displayed on the bead surface, whereas the inner core of each bead contained the corresponding linear encoding peptide. After screening of the cyclic peptide library, the identity of hit peptides was determined by sequencing the linear encoding peptides using a partial Edman degradation/mass spectrometry method. Using the same spatial segregation approach peptides were synthesized in the conventional C to N direction, with their C-termini attached to the support through an ester linkage on the bead surface but through an amide bond in the inner layer. The surface peptides were cyclized between N-terminal amine and a carboxyl group installed at a C-terminal linker sequence, while the internal peptides stayed in the linear form. Base hydrolysis of the ester linkage in the cyclic peptides exposed a free [alpha]-carboxyl group at the C-termini of the peptides attached to the resin via the N-termini. An inverted peptide library containing five random residues was synthesized and screened for binding to PDZ domains. The identity of the binding peptides was determined from the encoding peptides. Consensus recognition motifs were identified for the PDZ domains and representative peptides were individually synthesized and confirmed for binding to their cognate PDZ domains. These methods expanded the utility of OBOC peptide libraries by displaying peptides in different ways.
Download or read book Peptide Libraries written by Ratmir Derda and published by Humana. This book was released on 2016-09-24 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides an overview of modern and emerging methods for production, analysis, and utility of peptide libraries. Chapter focus on methods and techniques for synthesis, genetic expression, hybrid synthesis-expression, examples of modern utility of these libraries, de novo discovery of reactions, hybrid organic-inorganic materials and, emerging tools for the analysis of these libraries by method of genetic selection and next-generation sequencing. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Peptide Libraries: Methods and Protocols seeks to serve both professionals and novices with its well-honed methodologies.
Download or read book Combinatorial Peptide Library Protocols written by Shmuel Cabilly and published by Springer Science & Business Media. This book was released on 2008-02-02 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the course of evolution, an imbalance was created between the rate of vertebrate genetic adaptation and that of the lower forms of living organisms, such as bacteria and viruses. This imbalance has given the latter the advantage of generating, relatively quickly, molecules with unexpected structures and features that carry a threat to vertebrates. To compensate for their weakness, vertebrates have accelerated their own evolutionary processes, not at the level of whole organism, but in specialized cells containing the genes that code for antibody molecules or for T-cell receptors. That is, when an immediate requirement for molecules capable of specific interactions arose, nature has preferred to speed up the mode of Darwinian evolution in pref- ence to any other approach (such as the use of X-ray diffraction studies and computergraphic analysis). Recently, Darwinian rules have been adapted for test tube research, and the concept of selecting molecules having particular characteristics from r- dom pools has been realized in the form of various chemical and biological combinatorial libraries. While working with these libraries, we noticed the interesting fact that when combinatorial libraries of oligopeptides were allowed to interact with different selector proteins, only the actual binding sites of these proteins showed binding properties, whereas the rest of the p- tein surface seemed "inert. " This seemingly common feature of protein- having no extra potential binding sites--was probably selected during evolution in order to minimize nonspecific interactions with the surrounding milieu.
Download or read book Combinatorial Library written by Lisa B. English and published by Springer Science & Business Media. This book was released on 2008-02-04 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: The continued successes of large- and small-scale genome sequencing projects are increasing the number of genomic targets available for drug d- covery at an exponential rate. In addition, a better understanding of molecular mechanisms—such as apoptosis, signal transduction, telomere control of ch- mosomes, cytoskeletal development, modulation of stress-related proteins, and cell surface display of antigens by the major histocompatibility complex m- ecules—has improved the probability of identifying the most promising genomic targets to counteract disease. As a result, developing and optimizing lead candidates for these targets and rapidly moving them into clinical trials is now a critical juncture in pharmaceutical research. Recent advances in com- natorial library synthesis, purification, and analysis techniques are not only increasing the numbers of compounds that can be tested against each specific genomic target, but are also speeding and improving the overall processes of lead discovery and optimization. There are two main approaches to combinatorial library production: p- allel chemical synthesis and split-and-mix chemical synthesis. These approaches can utilize solid- or solution-based synthetic methods, alone or in combination, although the majority of combinatorial library synthesis is still done on solid support. In a parallel synthesis, all the products are assembled separately in their own reaction vessels or microtiter plates. The array of rows and columns enables researchers to organize the building blocks to be c- bined, and provides an easy way to identify compounds in a particular well.
Download or read book Peptide Synthesis and Applications written by John Howl and published by Springer Science & Business Media. This book was released on 2008-02-02 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hands-on experts describe in step-by-step detail the key methodologies of contemporary peptide synthesis and illustrate their numerous applications. The techniques presented include protocols for chemical ligation, the synthesis of cyclic and phosphotyrosine-containing peptides, lipoamino acid- and sugar-conjugated peptides, and peptide purification and analyses. Additional chapters detail methodologies and instrumentation for high-throughput peptide synthesis, many different applications of peptides as novel research tools and biological probes, and the design and application of fluorescent substrate-based peptides that can be used to determine the selectivity and activity of peptidases. A practical guide to the identification of proteins using mass spectrometric analyses of peptide mixtures is also included.
Download or read book Cyclic Peptides written by Jesko Koehnke and published by Royal Society of Chemistry. This book was released on 2017-12-14 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclic peptides are increasingly employed as chemical tools in biology and drug discovery. They have gained a lot of interest as alternative sources of new drugs to traditional small molecules. This book introduces cyclic peptides and provides a thorough overview of biosynthetic and fully synthetic approaches to their preparation. Following an introduction to cyclic peptides, biosynthetic and traditional chemical routes to cyclic peptides are reviewed. Due to their size, their synthesis is not trivial. Recent advances in the incorporation of novel structural units are presented in addition to how synthesis and biological methods can be combined. The chemical analysis of this molecular class is also discussed. Furthermore, chapters detail the progression of cyclic peptides as tools in biology and as potential drugs, providing a future vision of their importance. In total, this book provides the reader with a comprehensive view of the state-of-the-art of cyclic peptides, from construction to possible clinical utility. This book will be an essential resource for students, researchers and scientists within industry in medicinal, bioorganic, natural product and analytical chemistry fields.
Download or read book Peptides Across the Pacific Proceedings of the 23rd American Peptide Symposium and the 6th International Peptide Symposium written by Michal Lebl and published by Lulu.com. This book was released on 2013-09-30 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the symposium in June 2013 on Big Island, Hawaii
Download or read book New Methods for Synthesis and Modification of Peptides and Proteins written by Alexander Alexandrovich Vinogradov and published by . This book was released on 2017 with total page 261 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical modification of peptides and proteins is an enabling suite of tools for tailoring the properties of these biomolecules to specific applications. A number of bio-conjugation reactions allows fine-tuning of the biological activity, proteolytic stability, and immunogenicity of peptides and proteins, as well as equipping them with completely novel functions such as cell penetration, fluorescence, unique chemical reactivity, and much more. Described herein are a number of new methods for the synthesis of modified peptides and proteins, and an approach to the discovery of such methodologies. Applications of fast-flow solid phase peptide synthesis - a technique recently developed to accelerate and improve peptide synthesis- towards the synthesis of difficult sequences and the refinement of associated protocols is described. The utility of the system is demonstrated via rapid total synthesis of barnase, a model 110-residue RNase, in the L- and D-forms. Systematic characterization of the biochemical properties of the synthesized proteins revealed that barnase is able to hydrolyze substrates of various chiralities, and that D-barnase is fully proteolytically stable. Separately, a method for the preparation and utilization of unprotected peptide isocyanates in water was developed. It was shown that easily accessible C-terminal peptide isocyanates can be conjugated to a number of strong nucleophiles in the presence of unprotected amino acid side chains for peptides and proteins of various structures. Two-component macrocyclization of peptide isocyanates with bifunctional linkers was developed as an extension of the described chemistry. The resulting cyclic peptides were shown to be more proteolytically stable and more bioactive than their linear analogs. In pursuit of generalizing the C-terminal protein modification chemistry to fully proteogenic peptides and proteins, a number of library screening approaches was developed. Liquid chromatography coupled to tandem mass spectrometry was employed to screen and reliably decode synthetic peptide libraries in a high-throughput manner. These protocols were used to discover proteogenic sequence tags reactive towards substituted hydrazine derivatives in a transpeptidation reaction. The discovered C-terminal tripeptide tag His-Gly-Cys underwent transpeptidation with a number of structurally different nucleophiles in various sequence contexts.
Download or read book Peptide Macrocycles written by Matthew B. Coppock and published by Humana. This book was released on 2022-10-02 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume explores the latest techniques and strategies used to study the field of peptide macrocycles. The chapters in this book ae organized into four parts: macrocycles synthesis, combinational library synthesis and screening, macrocycle characterization, and unique applications. Part One looks at a variety of peptide cyclization methodologies, and Part Two describes methods for the creation of peptide macrocycles libraries and their subsequent screening against biological targets of interest. Part Three discusses the study and characterization of peptide macrocycle-target interactions, and Part Four introduces unique applications for peptide macrocycles, from higher-order structure formation to post-synthetic functional modifications. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and comprehensive, Peptide Macrocycles: Methods and Protocols is a valuable resource for both novice and expert researchers looking to learn more about this developing field.
Download or read book Cyclized Helical Peptides written by Zigang Li and published by John Wiley & Sons. This book was released on 2021-08-23 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important and timely guide to the progress being made on constrained helical peptides Constraint helical peptides have emerged as a solution to target previously undruggable protein-protein interactions, which feature large and complex surfaces. Cyclized Helical Peptides: Synthesis, Properties and Therapeutic Applications offers a review of the most current methodologies of constructing constrained helices. The authors noted experts on the topic include the information on the fundamental features of cyclized helical peptides and discuss their limitations. The book summarizes and explores the effects of chemical methods constructing helical peptides on helicity, binding affinity, cell penetration, and nonspecific toxicity. The book examines the therapeutic applications of the constraint helices and includes comparison with existing small molecule modulators or antibodies. Designed as a useful resource for both those outside and inside the field. Those new to the field will find a comprehensive introduction to cyclized helical peptide and those inside the field will find a deeper understanding of the topic. This important book: Offers a practical introduction to constrained helical peptides Includes all aspects of constrained helical peptides Includes information on the most recent methods that have emerged Presents a guide to help solve practical problems in the field Written for academics, pharmaceutical professional, Cyclized Helical Peptides is a comprehensive guide to the developments of constrained helical peptides.
Download or read book Part I Application of 2 Hydroxymethylacrylic Acid a Product of Baylis Hillman Reaction for the Synthesis of Novel N backbone to Side Chain Cyclic Peptide Analogs Strategies and Side Reactions Part II Synthesis and Biological Activities of Chimeric Bioactive Peptides Featuring Amino Acids Coupled to 4 Anilino N Phenethyl Piperidine written by Ravil Rashitovich Petrov and published by . This book was released on 2007 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt: During my research career in Prof. V.J. Hruby's laboratory I worked on two different projects. The first project, which was initiated by the author, was planned to serve the need of our laboratory for a novel method of peptide cyclization. This method was planned to use recent advances in Pd0-catalyzed asymmetric synthesis combined with the structural richness offered by the Baylis-Hillman chemistry which could open new ways to diverse areas of drug design, molecular immunology and chemotherapy. This approach would provide cyclic peptides featuring N-alkylated amino acids that would confer high resistance to degradation by proteases. Because of numerous synthetic problems imposed, this strategy was not of considerable current use in peptide synthesis, especially on solid supports. However, despite a substantial amount of effort invested, this method faced serious drawbacks such as multistep synthesis and side reactions when applied to solid supports. Moreover, recent introduction of microwave technology which has helped to solve a great number of problems has led to a renaissance in the classical lactam and thioester bond cyclizations which overshadowed our quest for a novel methodology. The second project was focused on application of 4-anilidopiperidines for the synthesisof chimeric bioactive peptides. It was an effort towards the development of novel analgesics with reduced toxicity and enhanced potency. This project linked small molecule and multimeric ligand designs that were ongoing in our laboratory at the time. Major accomplishments in this project were made possible by successful resolution of several research challenges. I was able to find a straightforward, convenient and economical approach for the synthesis of novel analogues on a solid support. These developments led to novel compounds which showed substantial increases in their binding affinity relative to corresponding opioid analogues. To illustrate, compounds PET25, 26, 27, 29, 30, 31, and 32 showed high bioactivity and sub-nanomolar binding affinity to opioid receptors. Most of the peptides generated in the second project are still being investigated for their biological activities by our colleagues at the Department of Pharmacology, but the results to date indicate that some highly potent novel compounds have been made.
Download or read book Combinatorial Synthesis Sequencing and Biological Applications of Peptide and Peptidomimetic Libraries written by Amit Thakkar and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have also successfully synthesized and sequenced support-bound cyclic peptoids, a novel class of compounds. By using a one-bead, two-compound approach, we have spatially segregated TentaGel microbeads (90 um) and synthesized a cyclic peptoid on the bead exterior to be used for biological screenings and a linear peptoid on the bead interior for sequencing by PED/MS. Cyclic peptoid libraries were used to investigate potential protein inhibitors and determine streptavidin ligands.
Download or read book Principles of Peptide Synthesis written by M. Bodanszky and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: A look at the shelves of a major library awakens doubts in the author of this small volume about the importance of writing a new introduction to peptide synthesis. This rather narrow area of bio-organic chemistry already has received considerable attention. A whole series of books deals with the synthesis of peptides. Some of these are textbooks written to support lecture courses on peptide synthesis. Others try to help the beginner, otherwise well versed in organic chemistry, to embark on some experimental project that requires the construction of peptide chains. Not less useful are the monographs which were compiled to aid the adept practitioner and to provide him with references to the growing literature of a very active field. Is there any need for a new book on peptide synthesis? Should we add a new volume to an already impressive and certainly useful series? The answer is not obvious. The author has already participated in two similar en deavors. The first edition! of "Peptide Synthesis", with M. A. Ondetti as coauthor, was meant to serve as an introduction for the beginner. It was rather well received by researchers who joined the field of peptide chemistry and were looking for initiation. While working on the 2 second edition with Drs. Klausner and Ondetti, we became painfully aware of the impossibility of the task.
Download or read book Investigations Into the Biomimetic Synthesis Structural Determination and Therapeutic Development of Antimicrobial Peptides written by Keith Mathew Wilcoxen and published by . This book was released on 2002 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleophilic catalysis of acyl transfer reactions is a fundamental theme in the biological synthesis of many naturally occurring biopolymers and natural products. Catalytic amide bond formation has proven to be a versatile and ubiquitous method for the biosynthesis of proteins and non-ribosomal peptides. Many of these non-ribosomal peptides exhibit therapeutic properties and are used in nature as a first line of defense in innate immunity. Biomimetic, stoichiometric acyl-transfer catalysts built from coiled-coil peptide constructs have been designed, synthesized, and characterized. In an effort to mimic the directed inter-modular aminoacyl-transfer reaction found in nonribosomal peptide synthases, helical bundles based on the GCN4 sequence were engineered to contain active sites comprised of aminoacyl donor (cysteine) and acceptor (lysine) moieties. Catalytic activities involving loading of thiol ester substrates via transthiolesterification, acyl transfer, and reloading of substrate onto the reformed cysteine were evaluated in terms of rate constant of acyl-group transfer. These data show that the designed peptides significantly accelerate the rate of aminoacyl transfer between non-covalently interacting species. Cyclic peptides have come under scrutiny as potential antimicrobial therapeutic agents. Combinatorial split-and-pool synthesis of cyclic peptides can afford single compound per well libraries for antimicrobial screening, new lead identification, and construction of QSAR. Here we report a new sequencing protocol for rapid identification of the members of a cyclic peptide library based on automated computer analysis of mass spectra, obviating the need for library encoding/decoding strategies. In addition, the automated MS (mass spectrometry) driven sequencing strategy and its application toward large split and pool libraries of antimicrobial D, L-cyclic peptides is described. Antimicrobial peptides were synthesized in a parallel and split and pool format. Directed libraries (600 to 20,000 members) were synthesized on macrobead resins and single beads were isolated and cleaved to provide individual cyclic peptide compounds. Compounds were assayed for antibacterial activity against antibiotic resistant bacteria. Active and inactive peptides were assessed for purity and identity by LC/MS and automated sequencing. Peptides of interest were individually synthesized and assayed for validation (>120 compounds). Molecular descriptors were used to establish preliminary SAR, gain insight into mode of action and provide criteria for therapeutic selectivity between gram-negative bacteria, gram-positive bacteria and eukaryotic cells.
