Crystal structure of the maltose transporter in a pretranslocation intermediate state.Oldham, M.L., Chen, J.
(2011) Science 332: 1202-1205
- PubMed: 21566157
- DOI: https://doi.org/10.1126/science.1200767
- Primary Citation of Related Structures:
3PUY, 3PUZ, 3PV0
- PubMed Abstract:
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.
Department of Biological Sciences, Purdue University, Howard Hughes Medical Institute, West Lafayette, IN 47907, USA.