Phospholipid translocation captured in a bifunctional membrane protein MprF

Nat Commun. 2021 May 18;12(1):2927. doi: 10.1038/s41467-021-23248-z.

Abstract

As a large family of membrane proteins crucial for bacterial physiology and virulence, the Multiple Peptide Resistance Factors (MprFs) utilize two separate domains to synthesize and translocate aminoacyl phospholipids to the outer leaflets of bacterial membranes. The function of MprFs enables Staphylococcus aureus and other pathogenic bacteria to acquire resistance to daptomycin and cationic antimicrobial peptides. Here we present cryo-electron microscopy structures of MprF homodimer from Rhizobium tropici (RtMprF) at two different states in complex with lysyl-phosphatidylglycerol (LysPG). RtMprF contains a membrane-embedded lipid-flippase domain with two deep cavities opening toward the inner and outer leaflets of the membrane respectively. Intriguingly, a hook-shaped LysPG molecule is trapped inside the inner cavity with its head group bent toward the outer cavity which hosts a second phospholipid-binding site. Moreover, RtMprF exhibits multiple conformational states with the synthase domain adopting distinct positions relative to the flippase domain. Our results provide a detailed framework for understanding the mechanisms of MprF-mediated modification and translocation of phospholipids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Binding Sites / genetics
  • Biological Transport
  • Cell Membrane / metabolism
  • Cryoelectron Microscopy
  • Lysine / chemistry
  • Lysine / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Models, Molecular
  • Phosphatidylglycerols / chemistry
  • Phosphatidylglycerols / metabolism*
  • Phospholipids / chemistry
  • Phospholipids / metabolism*
  • Protein Binding
  • Protein Conformation
  • Protein Multimerization
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism*
  • Recombinant Proteins / ultrastructure
  • Rhizobium tropici / genetics
  • Rhizobium tropici / metabolism

Substances

  • Bacterial Proteins
  • Membrane Proteins
  • Phosphatidylglycerols
  • Phospholipids
  • Recombinant Proteins
  • lysylphosphatidylglycerol
  • Lysine