Towards the functional characterization and inhibition of hydrolase enzymes in mycobacteria (972.5)

Abstract

The emergence of multiple and extremely drug‐resistant strains of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB) in humans, threatens the usefulness of our current therapeutic arsenal. As a result, there is an increasing need to identify novel mycobacterial targets that may lead to shorter, more effective treatment regimens. One promising group of potential targets is the serine hydrolases, which have diverse activities, but use a conserved nucleophilic serine residue for catalysis. In Mtb, many SHs have essential functions for Mtb survival, which makes the SH family a promising candidate for drug screening in mycobacteria. Using activity‐based probe profiling, the SH proteomes were visualized in three mycobacterial species that serve as models for virulent Mtb. Distinct populations of proteins were detect in the cell envelope versus the cytosol and between species. Importantly, mass spectrometry analysis of the SH proteome from attenuated Mtb identified known SHs, bioinformatically predicted SHs, and unannotated proteins as SHs. Furthermore, pre‐treatment of attenuated Mtb lysates with small‐molecule inhibitors resulted in concentration‐dependent inhibition of select enzymes. In conclusion, these data suggests that interspecies differences in the mycobacterial SH proteome can aid in understanding Mtb pathogenesis and that using activity‐based probe profiling will help identify selective inhibitors that have potential antimicrobial activity or can be used for characterizing newly annotated SHs. Therefore in the future, we will pursue small‐molecule screens to identify inhibitors that will aid in the functional characterization of these newly annotated SHs. Grant Funding Source: Supported by NIGMS T32‐GM008444, NIGMS T32‐GM092714, and the American Lung Association