3puz

Publication Abstract from PubMed

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters convert chemical energy from ATP hydrolysis to mechanical work for substrate translocation. They function by alternating between two states, exposing the substrate-binding site to either side of the membrane. A key question that remains to be addressed is how substrates initiate the transport cycle. Using x-ray crystallography, we have captured the maltose transporter in an intermediate step between the inward- and outward-facing states. We show that interactions with substrate-loaded maltose-binding protein in the periplasm induce a partial closure of the MalK dimer in the cytoplasm. ATP binding to this conformation then promotes progression to the outward-facing state. These results, interpreted in light of biochemical and functional studies, provide a structural basis to understand allosteric communication in ABC transporters.

Crystal structure of the maltose transporter in a pretranslocation intermediate state.,Oldham ML, Chen J Science. 2011 Jun 3;332(6034):1202-5. Epub 2011 May 12. PMID:21566157^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.