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Published January 28, 2014 | public
Journal Article

Structural and Mechanistic Diversity of ABC Transporters

Abstract

ATP Binding Cassette (ABC) transporters constitute a ubiquitous superfamily of integral membrane proteins responsible for the ATP powered membrane translocation of a wide variety of substrates. The highly conserved ABC domains defining the superfamily provide the nucleotide-powered engine that drives transport. In contrast, the transmembrane domains creating the translocation pathway are more variable, with three distinct folds currently recognized. Structural analyses of the high affinity methionine MetNI importer and of a bacterial homologue of the mitochondrial Atm1 exporter will be discussed within the mechanistic framework of the alternating access model. The interconversion of outward and inward facing conformations of the translocation pathway is coupled to the switching between open and closed interfaces of the ABC subunits that are associated with distinct nucleotide states. As observed for MetNI, additional domains may be present that can regulate transport activity. Building on this qualitative molecular framework for deciphering the transport cycle, an important goal is to develop quantitative models that detail the kinetic and molecular mechanisms by which ABC transporters utilize the binding and hydrolysis of ATP to power substrate translocation.

Additional Information

© 2014 Biophysical Society. Published by Elsevier Inc.

Additional details

Created:
August 19, 2023
Modified:
October 26, 2023