Membrane mediated toppling mechanism of the folate energy coupling factor transporter

Nat Commun. 2020 Apr 9;11(1):1763. doi: 10.1038/s41467-020-15554-9.

Abstract

Energy coupling factor (ECF) transporters are responsible for the uptake of micronutrients in bacteria and archaea. They consist of an integral membrane unit, the S-component, and a tripartite ECF module. It has been proposed that the S-component mediates the substrate transport by toppling over in the membrane when docking onto an ECF module. Here, we present multi-scale molecular dynamics simulations and in vitro experiments to study the molecular toppling mechanism of the S-component of a folate-specific ECF transporter. Simulations reveal a strong bending of the membrane around the ECF module that provides a driving force for toppling of the S-component. The stability of the toppled state depends on the presence of non-bilayer forming lipids, as confirmed by folate transport activity measurements. Together, our data provide evidence for a lipid-dependent toppling-based mechanism for the folate-specific ECF transporter, a mechanism that might apply to other ECF transporters.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry
  • ATP-Binding Cassette Transporters / genetics
  • ATP-Binding Cassette Transporters / metabolism*
  • Adenosine Triphosphate / metabolism
  • Archaea / genetics
  • Archaea / metabolism*
  • Archaeal Proteins / chemistry
  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism
  • Bacteria / genetics
  • Bacteria / metabolism*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Biological Transport
  • Cell Membrane / chemistry
  • Cell Membrane / metabolism*
  • Folic Acid / metabolism*
  • Lipid Bilayers / chemistry
  • Lipid Bilayers / metabolism
  • Models, Molecular
  • Protein Conformation

Substances

  • ATP-Binding Cassette Transporters
  • Archaeal Proteins
  • Bacterial Proteins
  • Lipid Bilayers
  • Adenosine Triphosphate
  • Folic Acid