Discovery of a novel stereospecific β-hydroxyacyl-CoA lyase/thioesterase shared by three metabolic pathways in Mycobacterium tuberculosis

The vast number of poorly characterised enzymes inMycobacterium tuberculosis(Mtb) is one of the key barriers precluding a better understanding of the biology that underpins pathogenesis. Here, we investigated the Mtb orphan enzyme Rv2498c to delineate its physiological role. Our results fromin vitroenzymatic assays, phylogenetic analysis, X-ray crystallography andin vivoMtb experiments, de-orphan Rv2498c as a multi-functional β-hydroxyacyl-CoA lyase/thioesterase (β-HAClyase/thioesterase) that participates in three different metabolic pathways: L-leucine catabolism, itaconate dissimilation, and glyoxylate shunt. Moreover, the deletion of therv2498cgene from the Mtb genome resulted in attenuation in the mouse model compared to infection with the parent strain. To the best of our knowledge, this is the first report of an (R)-3-hydroxyl-3-methylglutaryl-CoA for leucine catabolism and an itaconate-specific resistance mechanism in Mtb.