A photoactivated, site-selective conjugation of poly(ethylene glycol) (PEG) to the glutathione (GSH) binding pocket of glutathione S-transferase (GST) is described. To achieve this, a GSH analogue (GSH-BP) was designed and chemically synthesized with three functionalities: (1) the binding affinity of GSH to GST, (2) a free thiol for polymer functionalization, and (3) a photoreactive benzophenon...

The trapping of a sulfenic acid within the fully active C165S mutant of the AhpC peroxidase protein from Salmonella typhimurium was investigated. The electrophilic reagent employed in these studies, 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl), has previously been used to modify thiol, amino, and tyrosine hydroxyl groups in proteins; at neutral pH only cysteinyl residues of AhpC proteins are...

Clickable nanogel solutions were synthesized by using the copper catalyzed azide/alkyne cycloaddition (CuAAC) to partially polymerize solutions of azide and alkyne functionalized poly(ethylene glycol) (PEG) monomers. Coatings were fabricated using a second click reaction: a UV thiol-yne attachment of the nanogel solutions to mercaptosilanated glass. Because the CuAAC reaction was effectively ha...

A number of 1,3,4-oxadiazole, 3-9, and 1,2,4-triazole derivatives, 13-15, were synthesized starting form the acid hydrazide 1. The 1,3,4-thiadiazole derivative 12 was prepared from the substituted phenylthiosemicarbazide derivative 11 by treatment with sulfuric acid. The aryl hydrazone derivatives 10a-c were synthesized by reaction of the hydrazide 1 with the corresponding ketones. The thioalky...

Post-translational modifications (PTMs) are used by organisms to control protein structure and function after translation, but their study is complicated roles not often well understood as PTMs difficult introduce onto proteins selectively. Designing reagents that both good mimics of PTMs, also only modify select amino acid residues in challenging. Frequently, a chemical warhead linker used, cr...

The reagent 2-iminothiolane (2-IT) is used to introduce thiol groups into proteins and peptides by reactions of their amino groups. In this study, we report that the thiol adduct initially formed by the reaction of an amine with 2-IT (a 4-mercaptobutyramidine) is unstable and decays by a first-order process to a nonthiol product (an N-substituted 2-iminothiolane) with the loss of ammonia. The t...

Escherichia coli RNA polymerase loses 55-65% of its catalytic activity on reaction with Nbf-Cl (4-choro-7-nitrobenzofurazan). This partial inactivation was shown to be the result of specific impairment of RNA-chain elongation, since initiation of RNA chains was not altered after treatment with Nbf-Cl. The site of reaction was shown to be a unique thiol on the beta-subunit. This thiol is not acc...