A Homologue of the Mycobacterium tuberculosis PapA5 Protein, Rif‐Orf20, Is an Acetyltransferase Involved in the Biosynthesis of Antitubercular Drug Rifamycin B by Amycolatopsis mediterranei S699

Toward antitubercular drugs. Rif-Orf20, a homologue of M. tuberculosis PapA5 protein, is an acetyltransferase that is responsible for the conversion of DMDARSV to DMRSV in rifamycin B biosynthesis. This enzyme, together with PapA5, represents a new class of acyltransferases. The enzyme also utilizes propionyl-CoA as substrate to give rise to a new analogue of rifamycin that appears, from spectroscopic results, to have the structure...