Structural and Functional Characterization of Phosphatidylinositol-Phosphate Biosynthesis in Mycobacteria

Meagan Belcher Dufrisne, Cristina G. Timóteo, Vasileios I. Petrou, Khuram U. Ashraf, Surajit Banerjee, Oliver B. Clarke, Helena Santos, Filippo Mancia

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

In mycobacteria, phosphatidylinositol (PI) acts as a common lipid anchor for key components of the cell wall, including the glycolipids phosphatidylinositol mannoside, lipomannan, and lipoarabinomannan. Glycolipids in Mycobacterium tuberculosis, the causative agent of tuberculosis, are important virulence factors that modulate the host immune response. The identity-defining step in PI biosynthesis in prokaryotes, unique to mycobacteria and few other bacterial species, is the reaction between cytidine diphosphate–diacylglycerol and inositol-phosphate to yield phosphatidylinositol-phosphate, the immediate precursor to PI. This reaction is catalyzed by the cytidine diphosphate–alcohol phosphotransferase phosphatidylinositol-phosphate synthase (PIPS), an essential enzyme for mycobacterial viability. Here we present structures of PIPS from Mycobacterium kansasii with and without evidence of donor and acceptor substrate binding obtained using a crystal engineering approach. PIPS from Mycobacterium kansasii is 86% identical to the ortholog from M. tuberculosis and catalytically active. Functional experiments guided by our structural results allowed us to further characterize the molecular determinants of substrate specificity and catalysis in a new mycobacterial species. This work provides a framework to strengthen our understanding of phosphatidylinositol-phosphate biosynthesis in the context of mycobacterial pathogens.

Original languageEnglish
Pages (from-to)5137-5151
Number of pages15
JournalJournal of Molecular Biology
Volume432
Issue number18
DOIs
Publication statusPublished - 21 Aug 2020

Keywords

  • CDP-alcohol phosphotransferase
  • crystallography
  • inositol-phosphate
  • tuberculosis

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