Structure and function of ABC transporters: the ATP switch provides flexible control.
ATP-binding cassette (ABC) transporters are ubiquitous integral membrane proteins that facilitate the transbilayer movement of ligands. They comprise, minimally, two transmembrane domains, which impart ligand specificity, and two nucleotide-binding domains (NBDs), which power the transport cycle. Almost 25 years of biochemistry is reviewed in light of the recent structure analyses resulting in the ATP-switch model for function in which the NBDs switch between a dimeric conformation, closed around two molecules of ATP, and a nucleotide-free, dimeric 'open' conformation. The flexibility of this switching mechanism has evolved to provide different kinetic control for different transporters and has also been co-opted to diverse functions other than transmembrane transport.
Linton
Kenneth J
KJ
MRC Clinical Sciences Centre, Imperial College Hammersmith Hospital Campus, London, UK. kenneth.linton@csc.mrc.ac.uk
Higgins
Christopher F
CF
D018528:ATP-Binding Cassette Transporters / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D006868:Hydrolysis; D008954:Models, Biological; D008958:Models, Molecular; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
D018528:ATP-Binding Cassette Transporters; D000255:Adenosine Triphosphate