Transmembrane helix 12 plays a pivotal role in coupling energy provision and drug binding in ABCB1

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dc.contributor.authorCrowley, Emily
dc.contributor.authorO'Mara, Megan
dc.contributor.authorKerr, Ian
dc.contributor.authorCallaghan, Richard
dc.date.accessioned2015-12-13T22:43:59Z
dc.date.issued2010
dc.date.updated2016-02-24T09:37:57Z
dc.description.abstractDescribing the molecular details of the multidrug efflux process of ABCB1, in particular the interdomain communication associated with bioenergetic coupling, continues to prove difficult. A number of investigations to date have implicated transmembrane helix 12 (TM12) in mediating communication between the transmembrane domains and nucleotide-binding domains (NBDs) of ABCB1. The present investigation further addressed the role of TM12 in ABCB1 by characterizing its topography during the multidrug efflux process with the use of cysteine-directed mutagenesis. Cysteines were introduced at various positions along TM12 and assessed for their ability to covalently bind thiol-reactive fluorescent probes with differing physiochemical properties. By analysing each isoform in the basal, ATP-bound and posthydrolytic states, it was possible to determine how the local environment of TM12 alters during the catalytic cycle. Labelling with hydrophobic CM and zwitterionic BM was extensive throughout the helix in the basal, prehydrolytic and posthydrolytic states, suggesting that TM12 is in a predominantly hydrophobic environment. Overall, the carboxy region (intracellular half) of TM12 appeared to be more responsive to changes in the catalytic state of the protein than the amino region (extracellular half). Thus, the carboxy region of TM12 is suggested to be responsive to nucleotide binding and hydrolysis at the NBDs and therefore directly involved in interdomain communication. This data can be reconciled with an atomic-scale model of human ABCB1. Taken together, these results indicate that TM12 plays a key role in the progression of the ATP hydrolytic cycle in ABCB1 and, in particular, in coordinating conformational changes between the NBDs and transmembrane domains.
dc.identifier.issn1742-464X
dc.identifier.urihttp://hdl.handle.net/1885/79453
dc.publisherBlackwell Publishing Ltd
dc.sourceThe FEBS Journal
dc.subjectKeywords: adenosine triphosphate; multidrug resistance protein 1; protein; protein tm12; unclassified drug; article; covalent bond; drug binding; energy; human; priority journal; protein analysis; protein conformation; protein domain; Animals; Binding Sites; Cataly ABC transporter; bioenergetic coupling; drug resistance; efflux pumps; P-glycoprotein
dc.titleTransmembrane helix 12 plays a pivotal role in coupling energy provision and drug binding in ABCB1
dc.typeJournal article
local.bibliographicCitation.issue19
local.bibliographicCitation.lastpage3985
local.bibliographicCitation.startpage3974
local.contributor.affiliationCrowley, Emily, University of Oxford
local.contributor.affiliationO'Mara, Megan, University of Queensland
local.contributor.affiliationKerr, Ian, University of Nottingham
local.contributor.affiliationCallaghan, Richard, College of Medicine, Biology and Environment, ANU
local.contributor.authoremailu5103268@anu.edu.au
local.contributor.authoruidCallaghan, Richard, u5103268
local.description.embargo2037-12-31
local.description.notesImported from ARIES
local.identifier.absfor060110 - Receptors and Membrane Biology
local.identifier.absfor060112 - Structural Biology (incl. Macromolecular Modelling)
local.identifier.absfor060199 - Biochemistry and Cell Biology not elsewhere classified
local.identifier.absseo970106 - Expanding Knowledge in the Biological Sciences
local.identifier.ariespublicationf5625xPUB7891
local.identifier.citationvolume277
local.identifier.doi10.1111/j.1742-4658.2010.07789.x
local.identifier.scopusID2-s2.0-77956635483
local.identifier.thomsonID000281850200010
local.identifier.uidSubmittedByf5625
local.type.statusPublished Version

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