Function Analysis of Organophosphate Pesticides Hydrolase from Pseudomonas stutzeri HS-D36

In this paper, a novel organophosphate- degrading bacterium HS-D36 belonging to Pseudomonas stutzeri was reported. This bacterium has a strong ability to hydrolyze methyl parathion and the organophosphate pesticides hydrolase gene (oph) was cloned for the organophosphate hydrolase (OPH) function analysis. The oph gene was expressed in Escherichia coli BL21 (DE3) by using pET-28 expression system. The activity of the recombinant OPH in crude extracts reached 52.5 U ldr ml . Thermal stability experiment showed that the enzyme inactivated little for 60 minutes at temperature below 50degC. Further, the sequence alignment and phylogenetic analysis suggested that the OPH protein from the strain HS-D36 was 99.0% similar to MPD protein from Pseudomonas sp. WBC-3 and may be originated from metallo-beta-lactamases family. The protein structure prediction results suggested that the mature OPH comprise two independent subunits, each is composed of an active metal center (Zn
²⁺
and Cd
²⁺
).