Mining of aminotransferase gene ota3 from Bacillus pumilus W3 via genome analysis, gene cloning and expressing for compound bioamination

摘要

Aminotransferases are widely employed as biocatalysts to produce chiral amines and biologically active pharmaceuticals via asymmetric synthesis. In this study, transaminase genes in the Bacillus pumilus W3 genome were analysed, and gene ota3 encoding a putative (R)-selective transaminase was identified. The sequence of ota3 shares highest sequence identity (24.7%) with the first (R)-selective aminotransferase from Arthrobacter sp. KNK 168. Amino acid sequence and conserved domains analyses indicated that omega-BPAT encoded by ota3 belonged to the pyridoxal 5'-phosphate-dependent class IV (PLPDE_IV) superfamily. Both native and codon-optimised omega-BPAT genes were recombinantly expressed, and the purified proteins had a molecular mass of similar to 33.4 kDa. Furthermore, enantioselectivity tests with (S)- and (R)-alpha-phenethylamine revealed its (R)-selectivity. The optimal conditions for catalytic reaction were 45 degrees C and pH 7.0, and omega-BPAT retained stability at 20 degrees C and pH 7.0. Thus, omega-BPAT is a novel (R)-selective aminotransferase with great potential as a universal biocatalyst.