Genetic Incorporation of a Reactive Isothiocyanate Group into Proteins. Issue 34 (15th July 2016)

• Record Type: Journal Article
• Authors: Xuan, Weimin; Li, Jack; Luo, Xiaozhou; Schultz, Peter G.
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 34(2016)
• Page Start: 10065
• Page End: 10068
• Publication Date: 2016-07-15
• Subjects: crosslink -- isothiocyanate -- lysine -- noncanonical amino acid -- thiourea; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201604891
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Methods for the site‐specific modification of proteins are useful for introducing biological probes into proteins and engineering proteins with novel activities. Herein, we genetically encode a novel noncanonical amino acid (ncAA) that contains an aryl isothiocyanate group which can form stable thiourea crosslinks with amines under mild conditions. We show that this ncAA (pNCSF) allows the selective conjugation of proteins to amine‐containing molecular probes through formation of a thiourea bridge. pNCSF was also used to replace a native salt bridge in myoglobin with an intramolecular crosslink to a proximal Lys residue, leading to increased thermal stability. Finally, we show that pNCSF can form stable intermolecular crosslinks between two interacting proteins. Abstract : A handy handle : A novel noncanonical amino acid (ncAA) that contains an aryl isothiocyanate group was genetically incorporated into proteins in E. coli . This ncAA allows the selective conjugation of proteins to amine‐containing molecules through formation of a thiourea bridge. It was also used to form intra‐ and intermolecular protein crosslinks through reaction with proximal Lys residues.