3EJ9

Structural and mechanistic analysis of trans-3-chloroacrylic acid dehalogenase activity

Summary for 3EJ9

• Entry DOI: 10.2210/pdb3ej9/pdb
• Related: 3EJ3 3EJ7
• Descriptor: Alpha-subunit of trans-3-chloroacrylic acid dehalogenase, Beta-subunit of trans-3-chloroacrylic acid dehalogenase (3 entities in total)
• Functional Keywords: trans-3-chloroacrylic acid dehalogenase, caad, dehalogenase, isomerase, hydrolase
• Biological source: Pseudomonas pavonaceae; More
• Total number of polymer chains: 6
• Total formula weight: 48006.86

Authors

Pegan, S.,Serrano, H.,Whitman, C.P.,Mesecar, A.D. (deposition date: 2008-09-17, release date: 2008-12-02, Last modification date: 2023-08-30)

Primary citation

Pegan, S.D.,Serrano, H.,Whitman, C.P.,Mesecar, A.D.
Structural and mechanistic analysis of trans-3-chloroacrylic acid dehalogenase activity.
Acta Crystallogr.,Sect.D, 64:1277-1282, 2008

PubMed Abstract: 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.

PubMed: 19018104
DOI: 10.1107/S0907444908034707

Experimental method

X-RAY DIFFRACTION (1.5 Å)