PMID: 17158291 , Related PDB id: 2NQ2

Authors:

Pinkett HW, Lee AT, Lum P, Locher KP, Rees DC

Title:

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

Journal:

Science. 2007 Jan 19;315(5810):373-7. 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.