Characterization of Phosphopantetheinyl Hydrolase from Mycobacterium tuberculosis

Abstract

Tuberculosis (TB), caused by Mycobacterium tuberculosis , was the leading cause of death from an infectious disease before COVID, yet the in vivo essentiality and function of many of the protein-encoding genes expressed by M. tuberculosis are not known. We biochemically characterize M. tuberculosis ’s phosphopantetheinyl hydrolase, PptH, a protein unique to mycobacteria that removes an essential posttranslational modification on proteins involved in synthesis of lipids important for the bacterium’s cell wall and virulence.

Redirecting raltitrexed from cancer cell thymidylate synthase to Mycobacterium tuberculosis phosphopantetheinyl transferase

“…Amidinoureas were identified as whole-cell active, on-target PptT inhibitors by the following criteria: They accumulate unchanged in Mtb ; are more potent at killing Mtb in proportion to the degree to which the expression of PptT is reduced in conditional knockdown (cKD) strains, an effect not seen for 19 other antimycobacterial agents; bind in the PptT active site in cocrystals; are inactive against Mtb -bearing certain preservation-of-function point mutations in PptT; and are inactive against Mtb with loss-of-function mutations in a newly discovered enzyme, phosphopantetheinyl hydrolase (PptH), that removes Ppt from holo-ACPs (Fig. 1A), augmenting the PptT inhibitory effect of the amidinoureas ( 7 , 18 , 19 ). Work on amidinoureas continues ( 20 , 21 ).…”