Structure of the ABC Transporter MsbA in Complex with ADP.Vanadate and Lipopolysaccharide
Abstract
Select members of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family couple ATP binding and hydrolysis to substrate efflux and confer multidrug resistance. We have determined the x-ray structure of MsbA in complex with magnesium, adenosine diphosphate, and inorganic vanadate (Mg.ADP.Vi) and the rough-chemotype lipopolysaccharide, Ra LPS. The structure supports a model involving a rigid-body torque of the two transmembrane domains during ATP hydrolysis and suggests a mechanism by which the nucleotide-binding domain communicates with the transmembrane domain. We propose a lipid ``flip-flop'' mechanism in which the sugar groups are sequestered in the chamber while the hydrophobic tails are dragged through the lipid bilayer.
- Publication:
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Science
- Pub Date:
- May 2005
- DOI:
- 10.1126/science.1107733
- Bibcode:
- 2005Sci...308.1028R
- Keywords:
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- BIOCHEM