Comparative genomics revealed key molecular targets to rapidly convert a reference rifamycin-producing bacterial strain into an overproducer by genetic engineering

Rifamycins are mainstay agents in treatment of many widespread diseases, but how an improved rifamycin producer can be created is still incompletely understood. Here, we describe a comparative genomic approach to investigate the mutational patterns introduced by the classical mutate-and-screen method in the genome of an improved rifamycin producer. Comparing the genuine of the rifamycin B overproducer Amycolatopsis mediterranei HP 130 with those of the reference strains A. mediterranei S699 and U32, we identified 250 variations, affecting 227 coding sequences (CDS), 109 of which were HP 130 specific since they were absent in both 5699 and U32. Mutational and transcriptional patterns indicated a series of genomic manipulations that nor only proved the causative effect of mutB2 (coding for methylmalonyl-CoA mutase large subunit) and argS2 (coding for arginyl tRNA synthetase) mutations on the overproduction of rifamycin, but also constituted a rational strategy to genetically engineer a reference strain into an overproducer. (C) 2014 international Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.