3EJ7 image
Entry Detail
PDB ID:
3EJ7
Keywords:
Title:
Structural and mechanistic analysis of trans-3-chloroacrylic acid dehalogenase activity
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2008-09-17
Release Date:
2008-12-02
Method Details:
Experimental Method:
Resolution:
1.90 Å
R-Value Free:
0.26
R-Value Work:
0.20
R-Value Observed:
0.20
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Alpha-subunit of trans-3-chloroacrylic acid dehalogenase
Mutations:R8A
Chain IDs:A, C, E, G, I, K
Chain Length:76
Number of Molecules:6
Biological Source:Pseudomonas pavonaceae
Polymer Type:polypeptide(L)
Description:Beta-subunit of trans-3-chloroacrylic acid dehalogenase
Chain IDs:B, D, F, H, J, L
Chain Length:70
Number of Molecules:6
Biological Source:Pseudomonas pavonaceae
Ligand Molecules
Primary Citation
Structural and mechanistic analysis of trans-3-chloroacrylic acid dehalogenase activity.
Acta Crystallogr.,Sect.D 64 1277 1282 (2008)
PMID: 19018104 DOI: 10.1107/S0907444908034707

Abstact

Trans-3-chloroacrylic acid dehalogenase (CaaD) is a critical enzyme in the trans-1,3-dichloropropene (DCP) degradation pathway in Pseudomonas pavonaceae 170. This enzyme allows bacteria to use trans-DCP, a common component in commercially produced fumigants, as a carbon source. CaaD specifically catalyzes the fourth step of the pathway by cofactor-independent dehalogenation of a vinyl carbon-halogen bond. Previous studies have reported an X-ray structure of CaaD under acidic conditions with a covalent modification of the catalytic betaPro1 residue. Here, the 1.7 A resolution X-ray structure of CaaD under neutral (pH 6.5) conditions is reported without the presence of the covalent adduct. In this new structure, a substrate-like acetate molecule is bound within the active site in a position analogous to the putative substrate-binding site. Additionally, a catalytically important water molecule was identified, consistent with previously proposed reaction schemes. Finally, flexibility of the catalytically relevant side chain alphaGlu52 is observed in the structure, supporting its role in the catalytic mechanism.

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