Properties of ARO a from Halomonas Variabilis

ABSTRACTThe aro A gene encoding enolpyruvyl-shikimate-3-phosphate synthase (EPSPS) of Halomonas variabilis HTG7 and conferring glyphosate tolerance, was cloned from the cosmid library. The secondary structure, subcellular localization, transmembrane region, and phylogenetic analysis were predicted and analyzed according to the deduced amino acid sequence of EPSPS respectively. Two mutants, which have EPSPS enzyme activity while losing the glyphosate tolerance, were selected using error-prone PCR. By comparison with the sequence of native and mutated aro A genes, we found that the tertiary structure and backbone were the same. The torsion angles of the variant residues were discussed with respect to their accessibility and their possible involvement in the catalytic process.