A pre-steady state kinetic analysis of the αY60W mutant of trans-3-chloroacrylic acid dehalogenase: implications for the mechanism of the wild-type enzyme.

ABSTRACT: The bacterial degradation of the nematicide 1,3-dichloropropene, an isomeric mixture, requires the action of trans- and cis-3-chloroacrylic acid dehalogenase (CaaD and cis-CaaD, respectively). Both enzymes are tautomerase superfamily members and share a core catalytic mechanism for the hydrolytic dehalogenation of the respective isomer of 3-haloacrylate. The observation that cis-CaaD requires two additional residues raises the question of how CaaD conducts a comparable reaction with fewer catalytic residues. As part of an effort to determine the basis for the apparently simpler CaaD-catalyzed reaction, the kinetic mechanism was determined by stopped-flow and chemical-quench techniques using a fluorescent mutant form of the enzyme, αY60W-CaaD, and trans-3-bromoacrylate as the substrate. The

SUBMITTER: Huddleston JP 

PROVIDER: S-EPMC3518313 | biostudies-literature | 2012 Nov

REPOSITORIES: biostudies-literature