Chemoselective functionalization of peptides and proteins to selectively introduce residues for detection, capture, or specific derivatization is of high interest to the synthetic community. Here we report a new method for the mild and effective mono-iodination of tyrosine residues in fully unprotected peptides. This method is highly chemoselective and compatible with a wide variety of functional groups. The introduced iodine can subsequently serve as a handle for further functionalization such as introduction of fluorescent dyes and thus be used for chemoselective labeling of isolated peptides.
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http://dx.doi.org/10.1021/acs.bioconjchem.6b00461 | DOI Listing |
Peptide stapling reactions represent powerful methods for structuring native α-helices to improve their bioactivity in targeting protein-protein interactions (PPIs). In light of a growing need for regio- and positionally selective stapling methods involving natural amino acid residues in their unprotected states, we report a rapid, mild, and highly chemoselective three-component stapling reation using a class of molecular linchpins based on 2-arylketobenzaldehydes (ArKBCHOs) that create a fluorescent staple, hereafter referred to as a Fluorescent Isoindole Crosslink (FlICk). This methodology offers positional selectivity favouring , + 4 helical staples comprising a lysine and cysteine, in the presence of competing nucleophiles on unprotected peptides.
View Article and Find Full Text PDFJACS Au
November 2024
Institute for Advanced Chemistry of Catalonia (IQAC), Spanish National Research Council (CSIC), C/ Jordi Girona 18-26, 08034 Barcelona, Spain.
Native chemical ligation (NCL) ligates two unprotected peptides in an aqueous buffer. One of the fragments features a C-terminal α-thioester functional group, and the second bears an N-terminal cysteine. The reaction mechanism depicts two steps: an intermolecular thiol-thioester exchange resulting in a transient thioester, followed by an intramolecular acyl shift to yield the final native peptide bond.
View Article and Find Full Text PDFInt J Mol Sci
November 2024
Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany.
Infertility, defined as the inability to obtain pregnancy after 12 months of regular unprotected sexual intercourse, has increased in prevalence over the past decades, similarly to chronic, allergic, autoimmune, or neurodegenerative diseases. A recent ARIA-MeDALL hypothesis has proposed that all these diseases are linked to dysbiosis and to some cytokines such as interleukin 17 (IL-17) and interleukin 33 (IL-33). Our paper suggests that endometriosis, a leading cause of infertility, is linked to endometrial dysbiosis and two key cytokines, IL-17 and IL-33, which interact with intestinal dysbiosis.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry, Rice University, Houston, Texas 77005, United States.
Pyroglutamate is a cyclic -terminal post-translational modification that occurs in both proteins and peptide hormones. The prevalence and biological roles of pyroglutamate are little understood, in part due to limited tools to identify, quantify, and manipulate its pyrrolidinone structure. Selective modification of pyroglutamate residues in complex polypeptides may provide unique tools to better understand its biological roles and to allow late-stage diversification of biologically active pyroglutamate-containing sequences.
View Article and Find Full Text PDFJ Mater Chem B
December 2024
Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via. Giorgieri 1, 34127 Trieste, Italy.
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