Single-site oxidation, cysteine 108 to cysteine sulfinic acid, in D-amino acid oxidase from Trigonopsis variabilis and its structural and functional consequences.

ABSTRACT: One of the primary sources of enzyme instability is protein oxidative modification triggering activity loss or denaturation. We show here that the side chain of Cys108 is the main site undergoing stress-induced oxidation in Trigonopsis variabilis d-amino acid oxidase, a flavoenzyme employed industrially for the conversion of cephalosporin C. High-resolution anion-exchange chromatography was used to separate the reduced and oxidized protein forms, which constitute, in a molar ratio of about 3:1, the active biocatalyst isolated from the yeast. Comparative analysis of their tryptic peptides by electrospray tandem mass spectrometry allowed unequivocal assignment of the modification as the oxidation of Cys108 into cysteine sulfinic acid. Cys108 is likely located on a surface-exposed protein reg

SUBMITTER: Slavica A 

PROVIDER: S-EPMC1317377 | biostudies-literature | 2005 Dec

REPOSITORIES: biostudies-literature