Crystal structure and catalytic mechanism of 4-methylmuconolactone methylisomerase.

ABSTRACT: When methyl-substituted aromatic compounds are degraded via ortho (intradiol)-cleavage of 4-methylcatechol, the dead-end metabolite 4-methylmuconolactone (4-ML) is formed. Degradation of 4-ML has only been described in few bacterial species, including Pseudomonas reinekei MT1. The isomerization of 4-ML to 3-methylmuconolactone (3-ML) is the first step required for the mineralization of 4-ML and is catalyzed by an enzyme termed 4-methylmuconolactone methylisomerase (MLMI). We identified the gene encoding MLMI in P. reinekei MT1 and solved the crystal structures of MLMI in complex with 3-ML at 1.4-A resolution, with 4-ML at 1.9-A resolution and with a MES buffer molecule at 1.45-A resolution. MLMI exhibits a ferredoxin-like fold and assembles as a tight functional homodimeric complex. We wer

SUBMITTER: Marin M 

PROVIDER: S-EPMC2781687 | biostudies-literature | 2009 Nov

REPOSITORIES: biostudies-literature