title: Active rhodanese lacking nonessential sulfhydryl groups has increased hydrophobic exposure not observed in wild-type enzyme.
abstract: Mutation of all nonessential cysteine residues to serines in rhodanese turns the enzyme into a form (C3S) that is fully active but less stable than wild type (WT). bis-ANS binding studies have shown that C3S has more hydrophobic exposure than WT, although both have similar secondary structures suggesting the flexibility of its structure. Activity of C3S falls once it binds bis-ANS, and covalent binding of bis-ANS to C3S is induced by light. bis-ANS binds to C3S in its C-terminal domain as is shown by gel electophoresis and proteolysis. bis-ANS binding makes the C-terminal domain more susceptible to trypsin cleavage.
authors.affiliation: Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA.
authors.forename: Yogeet
authors.initials: Y
authors.lastname: Kaur
authors.forename: Jesse
authors.initials: J
authors.lastname: Ybarra
authors.forename: Paul M
authors.initials: PM
authors.lastname: Horowitz
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D000818:Animals; D002417:Cattle; D003545:Cysteine / Q000737:chemistry; D004795:Enzyme Stability / Q000235:genetics; D005456:Fluorescent Dyes; D057927:Hydrophobic and Hydrophilic Interactions; D008027:Light; D010777:Photochemistry / Q000379:methods; D011485:Protein Binding; D011487:Protein Conformation; D012694:Serine / Q000737:chemistry; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism
chemical_list: D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D012694:Serine; C035763:5,5'-bis(8-(phenylamino)-1-naphthalenesulfonate); D013884:Thiosulfate Sulfurtransferase; D003545:Cysteine