Download MendeleyCrystal structures of native and inactivated cis-3-chloroacrylic acid dehalogenase: Implications for the catalytic and inactivation mechanisms.
Guo, Y., Serrano, H., Johnson Jr., W.H., Ernst, S., Hackert, M.L., Whitman, C.P.(2011) Bioorg Chem 39: 1-9
- PubMed: 21074239
- DOI: https://doi.org/10.1016/j.bioorg.2010.10.001
- Primary Citation of Related Structures:
3MF7, 3MF8 - PubMed Abstract:
The isomeric mixture of cis- and trans-1,3-dichloropropene constitutes the active component of a widely used nematocide known as Telone II®. The mixture is processed by various soil bacteria to acetaldehyde through the 1,3-dichloropropene catabolic pathway. The pathway relies on an isomer-specific hydrolytic dehalogenation reaction catalyzed by cis- or trans-3-chloroacrylic acid dehalogenase, known respectively as cis-CaaD and CaaD. Previous sequence analysis and crystallographic studies of the native and covalently modified enzymes identified Pro-1, His-28, Arg-70, Arg-73, Tyr-103, and Glu-114 as key binding and catalytic residues in cis-CaaD. Mutagenesis of these residues confirmed their importance to the dehalogenation reaction. Crystal structures of the native enzyme (2.01Å resolution) and the enzyme covalently modified at the Pro-1 nitrogen by 2-hydroxypropanoate (1.65Å resolution) are reported here. Both structures are at a resolution higher than previously reported (2.75Å and 2.1Å resolution, respectively). The conformation of the covalent adduct is strikingly different from that previously reported due to its interaction with a 7-residue loop (Thr-32 to Leu-38). The participation of another active site residue, Arg-117, in catalysis and inactivation was also examined. The implications of the combined findings for the mechanisms of catalysis and inactivation are discussed.
Organizational Affiliation:
Division of Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, TX 78712, USA.
