Molecular cloning and nucleotide sequencing of organophosphorus insecticide hydrolase gene from Arthrobacter sp strain B-5

The organophosphorus insecticide hydrolase (OPH) gene of Arthrobacter sp. s train B-5, isolated from turf green soil was cloned into Escherichia coli J M109. Three clones, termed EpB511, EpB521 and EpB531, exhibiting OPH activi ty were obtained. However, these three clones showed lower OF-degrading abi lity than strain B-5. A 7.7-kb inserted fragment of the plasmid pB521 harbo red by EpB521 was subcloned, resulting in construction of a plasmid, pB526, carrying the 2.6-kb inserted fragment with OF-degrading ability. In this s equence, an open reading frame (ORF) that encodes a 43,607 Da plolypeptide composed of 415 amino acids was identified. The N-terminal amino acid seque nce deduced from the nucleotide sequence was identical to that of purified OPHs. The deduced amino acid sequence was compared with the sequences in th e data bank and a 58.1% amino acid identity was found with the aryldialkylp hosphatase from Nocardia sp. strain B-l, an enzyme that possesses catalytic functions similar to OPH.