1QW7

Structure of an Engineered Organophosphorous Hydrolase with Increased Activity Toward Hydrolysis of Phosphothiolate Bonds

Summary for 1QW7

• Entry DOI: 10.2210/pdb1qw7/pdb
• Related: 1DPM
• Descriptor: Parathion hydrolase, COBALT (II) ION, SODIUM ION, ... (5 entities in total)
• Functional Keywords: organophosphorous hydrolase, phosphotriesterase, vx, rvx, 4-methylbenzylphosphonate, mutant, hydrolase
• Biological source: Brevundimonas diminuta
• Cellular location: Cell membrane; Peripheral membrane protein: P0A434
• Total number of polymer chains: 2
• Total formula weight: 73555.11

Authors

Mesecar, A.D.,Grimsley, J.K.,Holton, T.,Wild, J.R. (deposition date: 2003-09-01, release date: 2004-11-30, Last modification date: 2023-11-15)

Primary citation

Grimsley, J.K.,Calamini, B.,Wild, J.R.,Mesecar, A.D.
Structural and mutational studies of organophosphorus hydrolase reveal a cryptic and functional allosteric-binding site.
Arch.Biochem.Biophys., 442:169-179, 2005

PubMed Abstract: Organophosphorus hydrolase detoxifies a broad range of organophosphate pesticides and the chemical warfare agents (CWAs) sarin and VX. Previously, rational genetic engineering produced OPH variants with 30-fold enhancements in the hydrolysis of CWA and their analogs. One interesting variant (H254R) in which the histidine at position 254 was changed to an arginine showed a 4-fold increase in the hydrolysis of demetonS (VX analog), a 14-fold decrease with paraoxon (an insecticide), and a 183-fold decrease with DFP (sarin analog). The three-dimensional structure of this enzyme at 1.9A resolution with the inhibitor, diethyl 4-methylbenzylphosphonate (EBP), revealed that the inhibitor did not bind at the active site, but bound exclusively into a well-defined surface pocket 12 A away from the active site. This structural feature was accompanied by non-competitive inhibition of paraoxon hydrolysis by EBP with H254R, in contrast to the native enzyme, which showed competitive inhibition. These parallel structure-function characteristics identify a functional, allosteric site on the surface of this enzyme.

PubMed: 16188223
DOI: 10.1016/j.abb.2005.08.012

Experimental method

X-RAY DIFFRACTION (1.9 Å)