An inward-facing conformation of a putative metal-chelate-type ABC transporter

Science. 2007 Jan 19;315(5810):373-7. doi: 10.1126/science.1133488. Epub 2006 Dec 7.

Abstract

The crystal structure of a putative metal-chelate-type adenosine triphosphate (ATP)-binding cassette (ABC) transporter encoded by genes HI1470 and HI1471 of Haemophilus influenzae has been solved at 2.4 angstrom resolution. The permeation pathway exhibits an inward-facing conformation, in contrast to the outward-facing state previously observed for the homologous vitamin B12 importer BtuCD. Although the structures of both HI1470/1 and BtuCD have been solved in nucleotide-free states, the pairs of ABC subunits in these two structures differ by a translational shift in the plane of the membrane that coincides with a repositioning of the membrane-spanning subunits. The differences observed between these ABC transporters involve relatively modest rearrangements and may serve as structural models for inward- and outward-facing conformations relevant to the alternating access mechanism of substrate translocation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • ATP-Binding Cassette Transporters / chemistry*
  • Bacterial Proteins / chemistry*
  • Catalytic Domain
  • Crystallography, X-Ray
  • Dimerization
  • Haemophilus influenzae / chemistry*
  • Metals / metabolism
  • Models, Molecular
  • Protein Conformation
  • Protein Folding
  • Protein Structure, Quaternary
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Protein Subunits / chemistry

Substances

  • ATP-Binding Cassette Transporters
  • Bacterial Proteins
  • Metals
  • Protein Subunits

Associated data

  • PDB/2NQ2