The Development of Unnatural Amino Acid-based Probes and Methods for Biological Studies

The Development of Unnatural Amino Acid-based Probes and Methods for Biological Studies PDF Author: Ismail A. Ahmed
Publisher:
ISBN:
Category :
Languages : en
Pages : 418

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Book Description
Proteins form a diverse ensemble of dynamic structures to carry out all life-sustaining functions. Therefore, many efforts have gone into studying the structure-dynamics-function relationship of proteins using a wide range of techniques, including fluorescence and infrared (IR) spectroscopies. While very useful, intrinsic fluorescence and IR signals arising from the natural amino acid side chains within the protein are often insufficient or unable to provide the information needed to understand the biological question of interest. To this end, various extrinsic spectroscopic probes, such as fluorescent dyes, have been used to increase the information content in specific measurements and applications. However, incorporation of a foreign moiety into any protein unavoidably affects its native structure and dynamics; hence effort must be made to reduce such perturbation. In this regard, the overarching aim of this thesis is to develop novel spectroscopic probes based on scaffolds of natural amino acids (NAAs). Because of their small size and similarity to NAAs, such unnatural amino acid-based (UAA-based) probes are expected to be minimally perturbing. Specifically, we show that (1) 4-cyanotryptophan (4CN-Trp) is a blue fluorescent amino acid useful for fluorescence microscopy applications; (2) 4CN-Trp and DiO (a common dye used to stain membranes) are a useful FRET pair to study peptide-membrane interactions; (3) 4CN-Trp, and tryptophan constitutes a dual FRET-PET pair which was used to study peptide end-to-end termini interactions and protein ligand-binding; and (4) the functional group of 4CN-Trp, 4-cyanoindole can be used in the form of a nucleoside as a dual fluorescence-IR reporter for DNA-protein studies. Furthermore, we extended applications of previously known UAAs and showed (5) p-cyanophenylalanine is useful as a fluorescence-based pH sensor which we used to determine peptide pKa's and peptide membrane penetration kinetics and (6) we use a simple synthetic method for post-translationally installing an ester moiety on to proteins via cysteine alkylation as an UAA-based vibrational probe in proteins to study fibril formation and protein-ligand interactions

The Development of Unnatural Amino Acid-based Probes and Methods for Biological Studies

The Development of Unnatural Amino Acid-based Probes and Methods for Biological Studies PDF Author: Ismail A. Ahmed
Publisher:
ISBN:
Category :
Languages : en
Pages : 418

Get Book Here

Book Description
Proteins form a diverse ensemble of dynamic structures to carry out all life-sustaining functions. Therefore, many efforts have gone into studying the structure-dynamics-function relationship of proteins using a wide range of techniques, including fluorescence and infrared (IR) spectroscopies. While very useful, intrinsic fluorescence and IR signals arising from the natural amino acid side chains within the protein are often insufficient or unable to provide the information needed to understand the biological question of interest. To this end, various extrinsic spectroscopic probes, such as fluorescent dyes, have been used to increase the information content in specific measurements and applications. However, incorporation of a foreign moiety into any protein unavoidably affects its native structure and dynamics; hence effort must be made to reduce such perturbation. In this regard, the overarching aim of this thesis is to develop novel spectroscopic probes based on scaffolds of natural amino acids (NAAs). Because of their small size and similarity to NAAs, such unnatural amino acid-based (UAA-based) probes are expected to be minimally perturbing. Specifically, we show that (1) 4-cyanotryptophan (4CN-Trp) is a blue fluorescent amino acid useful for fluorescence microscopy applications; (2) 4CN-Trp and DiO (a common dye used to stain membranes) are a useful FRET pair to study peptide-membrane interactions; (3) 4CN-Trp, and tryptophan constitutes a dual FRET-PET pair which was used to study peptide end-to-end termini interactions and protein ligand-binding; and (4) the functional group of 4CN-Trp, 4-cyanoindole can be used in the form of a nucleoside as a dual fluorescence-IR reporter for DNA-protein studies. Furthermore, we extended applications of previously known UAAs and showed (5) p-cyanophenylalanine is useful as a fluorescence-based pH sensor which we used to determine peptide pKa's and peptide membrane penetration kinetics and (6) we use a simple synthetic method for post-translationally installing an ester moiety on to proteins via cysteine alkylation as an UAA-based vibrational probe in proteins to study fibril formation and protein-ligand interactions

Unnatural Amino Acids

Unnatural Amino Acids PDF Author: Loredano Pollegioni
Publisher: Humana Press
ISBN: 9781617793301
Category : Science
Languages : en
Pages : 409

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Book Description
Even though they are present in nature, non-proteinogenic amino acids are usually defined as unnatural or non-natural. Beside their structural diversity, interest in these compounds is due to their occurrence in nature, their biological properties, the analytical aspects, their use as probes, and their incorporation into peptides and proteins, among other reasons. Divided into five convenient sections, Unnatural Amino Acids: Methods and Protocols deals with enzymatic methods used to produce non-natural amino acids, aspects concerning the presence of unnatural amino acids in peptides with antimicrobial properties, genetic incorporation of unnatural amino acids into proteins (yeast and mammalian cells), and detection and quantification of D-amino acids and related enzymes. Written in the highly successful Methods in Molecular BiologyTM series format, chapters contain introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and notes on troubleshooting and avoiding known pitfalls. Authoritative and accessible, Unnatural Amino Acids: Methods and Protocols serves as an ideal guide for scientists and contributes to directing the attention of researchers to the many fields of growing scientific interest in non-natural amino acids.

Development of Novel Chemical Techniques to Address Biological Questions

Development of Novel Chemical Techniques to Address Biological Questions PDF Author: Johnathan C. Maza
Publisher:
ISBN:
Category : Amino acids
Languages : en
Pages : 182

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Book Description
The current biological toolkit has been vital in advancing our understanding of the world. That being said, the toolkit has limitations. As such, chemical biologists have been developing novel means to probe biological systems using chemical techniques. Bioorthogonal chemistry represents a new avenue to address biological questions that cannot be answered using current techniques. Herein, we describe a novel technique to probe proteins-of-interest using unnatural amino acid (UAA) mutagenesis. We have found that our UAAs allow us to access bioorthogonal chemistries for the conjugation of fluorophores to UAA-containing proteins. Additionally, we have extended these findings towards the application of protein immobilization. Finally, we used microwave technology to investigate novel means to transform bacterial cells with exogenous DNA.

Non-Natural Amino Acids

Non-Natural Amino Acids PDF Author:
Publisher: Academic Press
ISBN: 0080921639
Category : Science
Languages : en
Pages : 334

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Book Description
By combining the tools of organic chemistry with those of physical biochemistry and cell biology, Non-Natural Amino Acids aims to provide fundamental insights into how proteins work within the context of complex biological systems of biomedical interest. The critically acclaimed laboratory standard for 40 years, Methods in Enzymology is one of the most highly respected publications in the field of biochemistry. Since 1955, each volume has been eagerly awaited, frequently consulted, and praised by researchers and reviewers alike. With more than 400 volumes published, each Methods in Enzymology volume presents material that is relevant in today's labs -- truly an essential publication for researchers in all fields of life sciences. - Demonstrates how the tools and principles of chemistry combined with the molecules and processes of living cells can be combined to create molecules with new properties and functions found neither in nature nor in the test tube - Presents new insights into the molecular mechanisms of complex biological and chemical systems that can be gained by studying the structure and function of non-natural molecules - Provides a "one-stop shop" for tried and tested essential techniques, eliminating the need to wade through untested or unreliable methods

Chemical Probes in Biology

Chemical Probes in Biology PDF Author: Manfred P. Schneider
Publisher: Springer Science & Business Media
ISBN: 9781402017698
Category : Molecular probes
Languages : en
Pages : 430

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Book Description


Unnatural Amino Acids as Metal-mediated Probes of Biological Function

Unnatural Amino Acids as Metal-mediated Probes of Biological Function PDF Author: Bhaskar Bhushan
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description


Unnatural Amino Acids

Unnatural Amino Acids PDF Author: Loredano Pollegioni
Publisher: Humana Press
ISBN: 9781493958887
Category : Science
Languages : en
Pages : 409

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Book Description
Even though they are present in nature, non-proteinogenic amino acids are usually defined as unnatural or non-natural. Beside their structural diversity, interest in these compounds is due to their occurrence in nature, their biological properties, the analytical aspects, their use as probes, and their incorporation into peptides and proteins, among other reasons. Divided into five convenient sections, Unnatural Amino Acids: Methods and Protocols deals with enzymatic methods used to produce non-natural amino acids, aspects concerning the presence of unnatural amino acids in peptides with antimicrobial properties, genetic incorporation of unnatural amino acids into proteins (yeast and mammalian cells), and detection and quantification of D-amino acids and related enzymes. Written in the highly successful Methods in Molecular BiologyTM series format, chapters contain introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and notes on troubleshooting and avoiding known pitfalls. Authoritative and accessible, Unnatural Amino Acids: Methods and Protocols serves as an ideal guide for scientists and contributes to directing the attention of researchers to the many fields of growing scientific interest in non-natural amino acids.

Unnatural Amino Acids Designed for Click Chemistry and Their Application to the Modification of Peptides & Nitrene Transfer Reactions Catalyzed by Metalloporphyrins

Unnatural Amino Acids Designed for Click Chemistry and Their Application to the Modification of Peptides & Nitrene Transfer Reactions Catalyzed by Metalloporphyrins PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 223

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Book Description
The field of peptidomimetics has rapidly grown into an area of great interest for the design and synthesis of pharmaceutical drug targets. The large array of natural peptides with biological function as well as the growing understanding of the roles of these peptides in biological events has led to a large interest in these compounds as drug candidates. The majority of peptide and peptide-like molecules have not found widespread pharmaceutical utility; however, due to there lability in biological systems. This major drawback leads to the necessity for the development of peptide-like molecules with increased stability under biological conditions. To this end there has been an increased interest in the development of unnatural amino acids for the synthetic modification of peptides and proteins. Presented in this dissertation is the synthesis of a series of unnatural amino acids designed for applications to [3+2] click cycloaddition reactions. It also covers the introduction of these amino acids into the sequence of peptides for the purpose of labeling the peptide with aryl triazole chromophores in an attempt to analyze the electron transfer capabilities of aryl triazoles. The information from the fluorescent studies of these peptides will provide a basis for the design of fluorophoric peptide probes that can be introduced into a peptide at any time under labile conditions. This methodology provides a powerful tool for the analysis of peptide structure and the analysis of peptide-macromolecular interactions.

The DESIGN AND SYNTHESIS OF NOVEL UNNATURAL AMINO ACIDS AND THE DESIGN AND SYNTHESIS OF PEPTIDES & PEPTIDOMIMETICS CONTAINING UNNATURAL AMINO ACIDS FOR THE STUDY OF G-PROTEIN COUPLED RECEPTORS.

The DESIGN AND SYNTHESIS OF NOVEL UNNATURAL AMINO ACIDS AND THE DESIGN AND SYNTHESIS OF PEPTIDES & PEPTIDOMIMETICS CONTAINING UNNATURAL AMINO ACIDS FOR THE STUDY OF G-PROTEIN COUPLED RECEPTORS. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 454

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Book Description
Nature has gifted peptides as important modulators in the human body, but these types of molecules often have not been favored when we were looking for therapeutic agents. The poor bioavailability, fast degradation and until recent high manufacturing costs of some bioactive peptides lowered their potential usage in the health industry. Under these circumstances, unnatural amino acids were developed as indispensible tools providing enormous support to peptide science. By incorporating proper unnatural amino acids into a peptide or protein, we now can significantly improve peptide's or protein's half-life, cell permeability, bio-distribution, etc. In addition, their potency and receptor/acceptor selectivity could also be enhanced. Site-specific modifications of peptides and proteins under physiological conditions with the use of unnatural amino acids also have been made easier with the advance of biotechnology. Therefore, my research described in this dissertation contributes to the efforts in the development of novel unnatural amino acids. In particular, I have focused on novel methods in the synthesis of anti beta-functionalized gamma, delta-unsaturated amino acids. These amino acids have special interests in peptide chemistry: they can provide conformational constraints to the peptide 3D structures; the beta-functionalization allows the introduction of pharmaceutically interesting side chain groups; and the terminal double bond which is orthogonal to peptide synthesis provides access to further chemical modifications. Two general methodologies for the synthesis of both racemic and optically active anti beta-functionalized gamma, delta--unsaturated amino acids were developed by using the thio-Claisen rearrangement (TCR) reaction. Excellent diastereoselectivies and enantioselectivities were obtained when C2-symmetric chiral auxiliaries were selected to control the stereochemistry outcome. The mechanism and the scope of the TCR reaction were also studied, showing unique advantages in the preparation of these biological interesting amino acids. Another effort of developing angiotensin II type 1 (AT1) receptor biased peptide ligands is also documented in this dissertation. The AT1 receptor is a 7-transmembrane G-protein coupled receptor, which recent researches have shown could be activated through a beta-arrestins only, but G-protein independent, pathway. We synthesized 12 analogs of Sar1,Ile4,Ile8-AngII (SII), and tested them in biological assays, and obtained valuable information for further "perfect" biased ligands design.

Fluorescent Analogs of Biomolecular Building Blocks

Fluorescent Analogs of Biomolecular Building Blocks PDF Author: Marcus Wilhelmsson
Publisher: John Wiley & Sons
ISBN: 1118175867
Category : Science
Languages : en
Pages : 474

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Book Description
Fluorescent Analogs of Biomolecular Building Blocks focuses on the design of fluorescent probes for the four major families of macromolecular building blocks. Compiling the expertise of multiple authors, this book moves from introductory chapters to an exploration of the design, synthesis, and implementation of new fluorescent analogues of biomolecular building blocks, including examples of small-molecule fluorophores and sensors that are part of biomolecular assemblies.