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Uptake or extrusion: crystal structures of full ABC transporters suggest a common mechanism
Author(s) -
Dawson Roger J. P.,
Hollenstein Kaspar,
Locher Kaspar P.
Publication year - 2007
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2007.05792.x
Subject(s) - atp binding cassette transporter , atp hydrolysis , transporter , biology , biochemistry , cytoplasm , transport protein , membrane transport protein , vesicular transport proteins , hydrolysis , plasma protein binding , biophysics , microbiology and biotechnology , atpase , enzyme , gene , vacuole , vacuolar protein sorting
Summary ATP‐binding cassette (ABC) transporters are integral membrane proteins that move diverse substrates across cellular membranes. ABC importers catalyse the uptake of essential nutrients from the environment, whereas ABC exporters facilitate the extrusion of various compounds, including drugs and antibiotics, from the cytoplasm. How ABC transporters couple ATP hydrolysis to the transport reaction has long remained unclear. The recent crystal structures of four complete ABC transporters suggest that a key step of the molecular mechanism is conserved in importers and exporters. Whereas binding of ATP promotes an outward‐facing conformation, the release of the hydrolysis products ADP and phosphate promotes an inward‐facing conformation. This basic scheme can in principle explain ATP‐driven drug export and binding protein‐dependent nutrient uptake.