Molecular cloning and expression of dihydropteroate synthase from M. Tuberculosis and M. Leprae

Abstract

Dihydropteroate synthase ( EC.2.5.1.15, DHPS ) is an obligatory enzyme in the de novo folate biosynthesis of prokaryotes and protozoan, whereas human cells can salvage and utilize exogeneous folates. Such a difference in folate metabolism has made DHPS an attractive target for chemotherapy. This research concerns the cloning and expression of DHPS from M. tuberculosis and M. leprae. Sufficient amounts of recombinant enzymes will provide opportunities for further studies that might lead to rational drug design of new effective anti-mycobacterial agents. The gene coding for DHPSs of M. tuberculosis and M. leprae were cloned from gDNA libraries by hybridization using probes derived from the polymerase chain reaction. DNA sequencing revealed an open-reading-frame of 840 bp, encoding a protein of 280 amino acids for M. tuberculosis DHPS, and of 852 bp encoding a protein of 284 amino acids for M. leprae DHPS. Both DHPSs were monofunctional enzymes.The enzymes were successfully expressed under the control of T5 promoter in a DHPS deficient strain of E. coliC600DfolP