Roles of active-site residues in catalysis, substrate binding, cooperativity, and the reaction mechanism of the quinoprotein glycine oxidase.

ABSTRACT: The quinoprotein glycine oxidase from the marine bacterium Pseudoalteromonas luteoviolacea (PlGoxA) uses a protein-derived cysteine tryptophylquinone (CTQ) cofactor to catalyze conversion of glycine to glyoxylate and ammonia. This homotetrameric enzyme exhibits strong cooperativity toward glycine binding. It is a good model for studying enzyme kinetics and cooperativity, specifically for being able to separate those aspects of protein function through directed mutagenesis. Variant proteins were generated with mutations in four active-site residues, Phe-316, His-583, Tyr-766, and His-767. Structures for glycine-soaked crystals were obtained for each. Different mutations had differential effects on k _cat and K _0.5 for catalysis, K _0.5

SUBMITTER: Mamounis KJ 

PROVIDER: S-EPMC7212659 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature