Two ZnF-UBP domains in isopeptidase T (USP5).

ABSTRACT: Human ubiquitin-specific cysteine protease 5 (USP5, also known as ISOT and isopeptidase T), an 835-residue multidomain enzyme, recycles ubiquitin by hydrolyzing isopeptide bonds in a variety of unanchored polyubiquitin substrates. Activation of the enzyme's hydrolytic activity toward ubiquitin-AMC (7-amino-4-methylcoumarin), a fluorogenic substrate, by the addition of free, unanchored monoubiquitin suggested an allosteric mechanism of activation by the ZnF-UBP domain (residues 163-291), which binds the substrate's unanchored diglycine carboxyl tail. By determining the structure of full-length USP5, we discovered the existence of a cryptic ZnF-UBP domain (residues 1-156), which was tightly bound to the catalytic core and was indispensable for catalytic activity. In contrast, the previously

SUBMITTER: Avvakumov GV 

PROVIDER: S-EPMC8391072 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature