Further Studies on the 3-Ketosteroid 9?-Hydroxylase of Rhodococcus ruber Chol-4, a Rieske Oxygenase of the Steroid Degradation Pathway

The biochemistry and genetics of the bacterial steroid catabolism have been extensively studied during last years their findings essential to development biotechnological applications. For instance, metabolic engineering steroid-eater strains has allowed obtain intermediaries industrial value. However, there are still some drawbacks that must be overcome, such as redundancy genes in genome a better knowledge its genetic regulation. KshABs KstDs key enzymes involved aerobic breakage nucleus. Rhodococcus ruber Chol-4 contains three kshAs genes, single kshB gene kstDs within genome. In present work, growth R. ?kshA was evaluated on different steroids substrates; promoter regions these were analyzed; expression followed by qRT-PCR both wild type ksh mutants. Additionally, transcription level results show KshA2B KshA1B AD metabolism, while KshA3B contribute cholesterol metabolism ruber. kshA mutants, remaining kstD is re-organized survive substrate. These data give insight into fine regulation when several isoforms present.