The Experts below are selected from a list of 152220 Experts worldwide ranked by ideXlab platform
Matthew B. Francis - One of the best experts on this subject based on the ideXlab platform.
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cucurbit 6 uril promoted click chemistry for Protein Modification
Journal of the American Chemical Society, 2017Co-Authors: Joel A Finbloom, Matthew B. Francis, Kenneth Han, Clancy C Slack, Ariel L FurstAbstract:Azide–alkyne cycloaddition is a powerful reaction for the formation of bioconjugates. When catalyzed by Cu(I) or strain promotion, this cycloaddition is considered to be a “click” reaction with many applications in chemical biology and materials science. We report a new type of azide–alkyne click chemistry for the synthesis of Protein conjugates using cucurbit[6]uril (CB6) supramolecular chemistry. CB6-promoted azide–alkyne cycloaddition has been previously used for the synthesis of rotaxanes but has not been applied to the development of complex bioconjugates. By developing new substrates for CB6 click that do not contain any cross-reactive functional groups and by optimizing reaction conditions, we converted CB6 click chemistry from a rotaxane synthesis tool into a useful bioconjugation technique. Using these new parameters, we synthesized a series of Protein conjugates including Protein–peptide, Protein–DNA, Protein–polymer, and Protein–drug conjugates. We further demonstrated that CB6 click can be use...
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targeting the n terminus for site selective Protein Modification
Nature Chemical Biology, 2017Co-Authors: Christian B Rosen, Matthew B. FrancisAbstract:The formation of well-defined Protein bioconjugates is critical for many studies and technologies in chemical biology. Tried-and-true methods for accomplishing this typically involve the targeting of cysteine residues, but the rapid growth of contemporary bioconjugate applications has required an expanded repertoire of Modification techniques. One very powerful set of strategies involves the Modification of Proteins at their N termini, as these positions are typically solvent exposed and provide chemically distinct sites for many Protein targets. Several chemical techniques can be used to modify N-terminal amino acids directly or convert them into unique functional groups for further ligations. A growing number of N-terminus-specific enzymatic ligation strategies have provided additional possibilities. This Perspective provides an overview of N-terminal Modification techniques and the chemical rationale governing each. Examples of specific N-terminal Protein conjugates are provided, along with their uses in a number of diverse biological applications.
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development of oxidative coupling strategies for site selective Protein Modification
Accounts of Chemical Research, 2015Co-Authors: Adel M Elsohly, Matthew B. FrancisAbstract:ConspectusAs the need to prepare ever more complex but well-defined materials has increased, a similar need for reliable synthetic strategies to access them has arisen. Accordingly, recent years have seen a steep increase in the development of reactions that can proceed under mild conditions, in aqueous environments, and with low concentrations of reactants. To enable the preparation of well-defined biomolecular materials with novel functional properties, our laboratory has a continuing interest in developing new bioconjugation reactions. A particular area of focus has been the development of oxidative reactions to perform rapid site- and chemoselective couplings of electron rich aromatic species with both unnatural and canonical amino acid residues.This Account details the evolution of oxidative coupling reactions in our laboratory, from initial concepts to highly efficient reactions, focusing on the practical aspects of performing and developing reactions of this type. We begin by discussing our rationa...
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controlled levels of Protein Modification through a chromatography mediated bioconjugation
Chemical Science, 2015Co-Authors: Richard L Kwant, Matthew B. Francis, Jake Jaffe, Peter J PalmereAbstract:Synthetically modified Proteins are increasingly finding applications as well-defined scaffolds for materials. In practice it remains difficult to construct bioconjugates with precise levels of Modification because of the limited number of repeated functional groups on Proteins. This article describes a method to control the level of Protein Modification in cases where there exist multiple potential Modification sites. A Protein is first tagged with a handle using any of a variety of Modification chemistries. This handle is used to isolate Proteins with a particular number of Modifications via affinity chromatography, and then the handle is elaborated with a desired moiety using an oxidative coupling reaction. This method results in a sample of Protein with a well-defined number of Modifications, and we find it particularly applicable to systems like Protein homomultimers in which there is no way to discern between chemically identical subunits. We demonstrate the use of this method in the construction of a Protein-templated light-harvesting mimic, a type of system which has historically been difficult to make in a well-defined manner.
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Oxidative Modification of Native Protein Residues Using Cerium(IV) Ammonium Nitrate
Journal of the American Chemical Society, 2011Co-Authors: Kristen Lee Seim, Allie C Obermeyer, Matthew B. FrancisAbstract:A new Protein Modification strategy has been developed that is based on an oxidative coupling reaction that targets electron-rich amino acids. This strategy relies on cerium(IV) ammonium nitrate (CAN) as an oxidation reagent and results in the coupling of tyrosine and tryptophan residues to phenylene diamine and anisidine derivatives. The methodology was first identified and characterized on peptides and small molecules, and was subsequently adapted for Protein Modification by determining appropriate buffer conditions. Using the optimized procedure, native and introduced solvent-accessible residues on Proteins were selectively modified with polyethylene glycol (PEG) and small peptides. This unprecedented bioconjugation strategy targets these under-utilized amino acids with excellent chemoselectivity and affords good-to-high yields using low concentrations of the oxidant and coupling partners, short reaction times, and mild conditions.
Goncalo J L Bernardes - One of the best experts on this subject based on the ideXlab platform.
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site selective Protein Modification chemistry for basic biology and drug development
Nature Chemistry, 2016Co-Authors: Nikolaus Krall, Goncalo J L Bernardes, Filipa P Da Cruz, Omar BoutureiraAbstract:Nature has produced intricate machinery to covalently diversify the structure of Proteins after their synthesis in the ribosome. In an attempt to mimic nature, chemists have developed a large set of reactions that enable post-expression Modification of Proteins at pre-determined sites. These reactions are now used to selectively install particular Modifications on Proteins for many biological and therapeutic applications. For example, they provide an opportunity to install post-translational Modifications on Proteins to determine their exact biological roles. Labelling of Proteins in live cells with fluorescent dyes allows Protein uptake and intracellular trafficking to be tracked and also enables physiological parameters to be measured optically. Through the conjugation of potent cytotoxicants to antibodies, novel anti-cancer drugs with improved efficacy and reduced side effects may be obtained. In this Perspective, we highlight the most exciting current and future applications of chemical site-selective Protein Modification and consider which hurdles still need to be overcome for more widespread use.
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a tag and modify approach to site selective Protein Modification
Accounts of Chemical Research, 2011Co-Authors: Justin M Chalker, Goncalo J L Bernardes, Benjamin G DavisAbstract:Covalent Modification can expand a Protein’s functional capacity. Fluorescent or radioactive labeling, for instance, allows imaging of a Protein in real time. Labeling with an affinity probe enables isolation of target Proteins and other interacting molecules. At the other end of this functional spectrum, Protein structures can be naturally altered by enzymatic action. Protein–Protein interactions, genetic regulation, and a range of cellular processes are under the purview of these post-translational Modifications. The ability of Protein chemists to install these covalent additions selectively has been critical for elucidating their roles in biology. Frequently the transformations must be applied in a site-specific manner, which demands the most selective chemistry. In this Account, we discuss the development and application of such chemistry in our laboratory. A centerpiece of our strategy is a “tag-and-modify” approach, which entails sequential installation of a uniquely reactive chemical group into the...
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chemical Modification of Proteins at cysteine opportunities in chemistry and biology
Chemistry-an Asian Journal, 2009Co-Authors: Justin M Chalker, Goncalo J L Bernardes, Yuya A Lin, Benjamin G DavisAbstract:Cys-tematic Modification: Cysteine is a versatile amino acid for selective chemical Modification of Proteins. Both chemical and biological innovations made possible by cysteine Modification are highlighted in this Focus Review. Chemical Modification of Proteins is a rapidly expanding area in chemical biology. Selective installation of biochemical probes has led to a better understanding of natural Protein Modification and macromolecular function. In other cases such chemical alterations have changed the Protein function entirely. Additionally, tethering therapeutic cargo to Proteins has proven invaluable in campaigns against disease. For controlled, selective access to such modified Proteins, a unique chemical handle is required. Cysteine, with its unique reactivity, has long been used for such Modifications. Cysteine has enjoyed widespread use in selective Protein Modification, yet new applications and even new reactions continue to emerge. This Focus Review highlights the enduring utility of cysteine in Protein Modification with special focus on recent innovations in chemistry and biology associated with such Modifications.
Seikoh Horiuchi - One of the best experts on this subject based on the ideXlab platform.
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ne carboxymethyl lysine and 3 dg imidazolone are major age structures in Protein Modification by 3 deoxyglucosone
Journal of Biochemistry, 2004Co-Authors: Tadashi Jono, Naila Ahmed, Motohiro Takeya, Ryoji Nagai, Seikoh HoriuchiAbstract:The levels of plasma 3-deoxyglucosone (3-DG) increase under hyperglycemic conditions and are associated with the pathogenesis of diabetic complications because of the high reactivity of 3-DG with Proteins to form advancedglycation end products (AGE). To investigate potential markers for 3-DG-mediated Protein Modification in vitro and in vivo, we compared the yield of several 3-DG-derived AGE structures by immunochemical analysis and HPLC and measured their localization in human atherosclerotic lesions. When BSA was incubated with 3-DG at 37°C for up to 4 wk, the amounts of N e -(carboxymethyl)lysine (CML) and 3-DG-imidazolone steeply increased with incubation time, whereas the levels of pyrraline and pentosidine increased slightly by day 28. In contrast, significants amount of pyrraline and pentosidine were also observed when BSA was incubated with 3-DG at 60°C to enhance AGE-formation. In atherosclerotic lesions, CML and 3-DG-imidazolone were found intracellularly in the cytoplasm of most foam cells and extracellularly in the atheromatous core. A weak-positive immunoreaction with pyrraline was found in the extracellular matrix and a few foam cells in aortic intima with atherosclerotic lesions. Our results provide the first evidence that CML and 3-DG-imidazolone are major AGE structures in 3-DG-modified Proteins, and that 3-DG-imidazolone provides a better marker for Protein Modification by 3-DG than pyrraline.
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ne carboxymethyl lysine and 3 dg imidazolone are major age structures in Protein Modification by 3 deoxyglucosone
Journal of Biochemistry, 2004Co-Authors: Tadashi Jono, Naila Ahmed, Motohiro Takeya, Ryoji Nagai, Xia Lin, Seikoh HoriuchiAbstract:The levels of plasma 3-deoxyglucosone (3-DG) increase under hyperglycemic conditions and are associated with the pathogenesis of diabetic complications because of the high reactivity of 3-DG with Proteins to form advanced glycation end products (AGE). To investigate potential markers for 3-DG-mediated Protein Modification in vitro and in vivo, we compared the yield of several 3-DG-derived AGE structures by immunochemical analysis and HPLC and measured their localization in human atherosclerotic lesions. When BSA was incubated with 3-DG at 37 degrees C for up to 4 wk, the amounts of N(epsilon)-(carboxymethyl)lysine (CML) and 3-DG-imidazolone steeply increased with incubation time, whereas the levels of pyrraline and pentosidine increased slightly by day 28. In contrast, significant amounts of pyrraline and pentosidine were also observed when BSA was incubated with 3-DG at 60 degrees C to enhance AGE-formation. In atherosclerotic lesions, CML and 3-DG-imidazolone were found intracellularly in the cytoplasm of most foam cells and extracellularly in the atheromatous core. A weak-positive immunoreaction with pyrraline was found in the extracellular matrix and a few foam cells in aortic intima with atherosclerotic lesions. Our results provide the first evidence that CML and 3-DG-imidazolone are major AGE structures in 3-DG-modified Proteins, and that 3-DG-imidazolone provides a better marker for Protein Modification by 3-DG than pyrraline.
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peroxynitrite induces formation of ne carboxymethyl lysine by the cleavage of amadori product and generation of glucosone and glyoxal from glucose novel pathways for Protein Modification by peroxynitrite
Diabetes, 2002Co-Authors: Ryoji Nagai, Yuka Unno, Miki Cristina Hayashi, Shuichi Masuda, Fumitaka Hayase, Naohide Kinae, Seikoh HoriuchiAbstract:Accumulation of advanced glycation end products (AGEs) on tissue Proteins increases with pathogenesis of diabetic complications and atherosclerosis. Here we examined the effect of peroxynitrite (ONOO(-)) on the formation of N( epsilon )-(carboxymethyl)lysine (CML), a major AGE-structure. When glycated human serum albumin (HSA; Amadori-modified Protein) was incubated with ONOO(-), CML formation was detected by both enzyme-linked immunosorbent assay and high-performance liquid chromatography (HPLC) and increased with increasing ONOO(-) concentrations. CML was also formed when glucose, preincubated with ONOO(-), was incubated with HSA but was completely inhibited by aminoguanidine, a trapping reagent for alpha-oxoaldehydes. For identifying the aldehydes that contributed to ONOO(-)-induced CML formation, glucose was incubated with ONOO(-) in the presence of 2,3-diaminonaphthalene. This experiment led to identification of glucosone and glyoxal by HPLC. Our results provide the first evidence that ONOO(-) can induce Protein Modification by oxidative cleavage of the Amadori product and also by generation of reactive alpha-oxoaldehydes from glucose.
Benjamin G Davis - One of the best experts on this subject based on the ideXlab platform.
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a tag and modify approach to site selective Protein Modification
Accounts of Chemical Research, 2011Co-Authors: Justin M Chalker, Goncalo J L Bernardes, Benjamin G DavisAbstract:Covalent Modification can expand a Protein’s functional capacity. Fluorescent or radioactive labeling, for instance, allows imaging of a Protein in real time. Labeling with an affinity probe enables isolation of target Proteins and other interacting molecules. At the other end of this functional spectrum, Protein structures can be naturally altered by enzymatic action. Protein–Protein interactions, genetic regulation, and a range of cellular processes are under the purview of these post-translational Modifications. The ability of Protein chemists to install these covalent additions selectively has been critical for elucidating their roles in biology. Frequently the transformations must be applied in a site-specific manner, which demands the most selective chemistry. In this Account, we discuss the development and application of such chemistry in our laboratory. A centerpiece of our strategy is a “tag-and-modify” approach, which entails sequential installation of a uniquely reactive chemical group into the...
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chemical Modification of Proteins at cysteine opportunities in chemistry and biology
Chemistry-an Asian Journal, 2009Co-Authors: Justin M Chalker, Goncalo J L Bernardes, Yuya A Lin, Benjamin G DavisAbstract:Cys-tematic Modification: Cysteine is a versatile amino acid for selective chemical Modification of Proteins. Both chemical and biological innovations made possible by cysteine Modification are highlighted in this Focus Review. Chemical Modification of Proteins is a rapidly expanding area in chemical biology. Selective installation of biochemical probes has led to a better understanding of natural Protein Modification and macromolecular function. In other cases such chemical alterations have changed the Protein function entirely. Additionally, tethering therapeutic cargo to Proteins has proven invaluable in campaigns against disease. For controlled, selective access to such modified Proteins, a unique chemical handle is required. Cysteine, with its unique reactivity, has long been used for such Modifications. Cysteine has enjoyed widespread use in selective Protein Modification, yet new applications and even new reactions continue to emerge. This Focus Review highlights the enduring utility of cysteine in Protein Modification with special focus on recent innovations in chemistry and biology associated with such Modifications.
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expanding the diversity of chemical Protein Modification allows post translational mimicry
Nature, 2007Co-Authors: Sander I Van Kasteren, Holger B Kramer, Henrik H Jensen, Sandra J Campbell, Joanna M Kirkpatrick, Neil J Oldham, Daniel C Anthony, Benjamin G DavisAbstract:One of the most important current scientific paradoxes is the economy with which nature uses genes. In all higher animals studied, we have found many fewer genes than we would have previously expected. The functional outputs of the eventual products of genes seem to be far more complex than the more restricted blueprint. In higher organisms, the functions of many Proteins are modulated by post-translational Modifications (PTMs). These alterations of amino-acid side chains lead to higher structural and functional Protein diversity and are, therefore, a leading contender for an explanation for this seeming incongruity. Natural Protein production methods typically produce PTM mixtures within which function is difficult to dissect or control. Until now it has not been possible to access pure mimics of complex PTMs. Here we report a chemical tagging approach that enables the attachment of multiple Modifications to bacterially expressed (bare) Protein scaffolds: this approach allows reconstitution of functionally effective mimics of higher organism PTMs. By attaching appropriate Modifications at suitable distances in the widely-used LacZ reporter enzyme scaffold, we created Protein probes that included sensitive systems for detection of mammalian brain inflammation and disease. Through target synthesis of the desired Modification, chemistry provides a structural precision and an ability to retool with a chosen PTM in a manner not available to other approaches. In this way, combining chemical control of PTM with readily available Protein scaffolds provides a systematic platform for creating probes of Protein-PTM interactions. We therefore anticipate that this ability to build model systems will allow some of this gene product complexity to be dissected, with the aim of eventually being able to completely duplicate the patterns of a particular Protein's PTMs from an in vivo assay into an in vitro system.
Seah Ling Kuan - One of the best experts on this subject based on the ideXlab platform.
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site selective Protein Modification via disulfide rebridging for fast tetrazine trans cyclooctene bioconjugation
Organic and Biomolecular Chemistry, 2020Co-Authors: Lujuan Xu, Marco Raabe, Maksymilian Marek Zegota, Joao C F Nogueira, Vijay Chudasama, Seah Ling KuanAbstract:An inverse electron demand Diels–Alder reaction between tetrazine and trans-cyclooctene (TCO) holds great promise for Protein Modification and manipulation. Herein, we report the design and synthesis of a tetrazine-based disulfide rebridging reagent, which allows the site-selective installation of a tetrazine group into disulfide-containing peptides and Proteins such as the hormone somatostatin (SST) and the antigen binding fragment (Fab) of human immunoglobulin G (IgG). The fast and efficient conjugation of the tetrazine modified Proteins with three different TCO-containing substrates to form a set of bioconjugates in a site-selective manner was successfully demonstrated for the first time. Homogeneous, well-defined bioconjugates were obtained underlining the great potential of our method for fast bioconjugation in emerging Protein therapeutics. The formed bioconjugates were stable against glutathione and in serum, and they maintained their secondary structure. With this work, we broaden the scope of tetrazine chemistry for site-selective Protein Modification to prepare well-defined SST and Fab conjugates with preserved structures and good stability under biologically relevant conditions.
