Energy coupling factor-type ABC transporters for vitamin uptake in prokaryotes

Biochemistry. 2012 Jun 5;51(22):4390-6. doi: 10.1021/bi300504v. Epub 2012 May 21.

Abstract

Energy coupling factor (ECF) transporters are a subgroup of ATP-binding cassette (ABC) transporters involved in the uptake of vitamins and micronutrients in prokaryotes. In contrast to classical ABC importers, ECF transporters do not make use of water-soluble substrate binding proteins or domains but instead employ integral membrane proteins for substrate binding (named S-components). S-components form active translocation complexes with the ECF module, an assembly of two nucleotide-binding domains (NBDs, or EcfA) and a second transmembrane protein. In some cases, the ECF module is dedicated to a single S-component, but in many cases, the ECF module can interact with several different S-components that are unrelated in sequence and bind diverse substrates. The modular organization with exchangeable S-components on a single ECF module allows the transport of chemically different substrates via a common route. The recent determination of the crystal structures of the S-components that recognize thiamin and riboflavin has provided a first clue about the mechanism of S-component exchange. This review describes recent advances and the current views of the mechanism of transport by ECF transporters.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry*
  • ATP-Binding Cassette Transporters / metabolism*
  • Bacteria / chemistry
  • Bacteria / metabolism*
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism*
  • Models, Molecular
  • Protein Conformation
  • Vitamins / metabolism*

Substances

  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Vitamins