Publication Date:
2011-05-14
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Oldham, Michael L -- Chen, Jue -- GM070515/GM/NIGMS NIH HHS/ -- Howard Hughes Medical Institute/ -- New York, N.Y. -- Science. 2011 Jun 3;332(6034):1202-5. doi: 10.1126/science.1200767. Epub 2011 May 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biological Sciences, Purdue University, Howard Hughes Medical Institute, West Lafayette, IN 47907, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21566157" target="_blank"〉PubMed〈/a〉
Keywords:
ATP-Binding Cassette Transporters/*chemistry/metabolism
;
Adenosine Triphosphate/metabolism
;
Amino Acid Motifs
;
Binding Sites
;
Biological Transport, Active
;
Catalytic Domain
;
Crystallization
;
Crystallography, X-Ray
;
Escherichia coli/*chemistry/metabolism
;
Escherichia coli Proteins/*chemistry/metabolism
;
Hydrogen Bonding
;
Maltose/metabolism
;
Maltose-Binding Proteins/chemistry/metabolism
;
Models, Biological
;
Models, Molecular
;
Monosaccharide Transport Proteins/*chemistry/metabolism
;
Periplasm/metabolism
;
Protein Conformation
;
Protein Multimerization
;
Protein Structure, Secondary
;
Protein Structure, Tertiary
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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