Transmembrane helix 12 modulates progression of the ATP catalytic cycle in ABCB1

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dc.contributor.authorCrowley, Emily
dc.contributor.authorO'Mara, Megan
dc.contributor.authorReynolds, Catherine
dc.contributor.authorTieleman, D. Peter
dc.contributor.authorStorm, Janet
dc.contributor.authorKerr, Ian
dc.contributor.authorCallaghan, Richard
dc.date.accessioned2015-12-13T22:45:54Z
dc.date.issued2009
dc.date.updated2016-02-24T09:41:32Z
dc.description.abstractMultidrug efflux pumps, such as P-glycoprotein (ABCB1), present major barriers to the success of chemotherapy in a number of clinical settings. Molecular details of the multidrug efflux process by ABCB1 remain elusive, in particular, the interdomain communication associated with bioenergetic coupling. The present investigation has focused on the role of transmembrane helix 12 (TM12) in the multidrug efflux process of ABCB1. Cysteine residues were introduced at various positions within TM12, and their effect on ATPase activity, nucleotide binding, and drug interaction were assessed. Mutation of several residues within TM12 perturbed the maximal ATPase activity of ABCB1, and the underlying cause was a reduction in basal (i.e., drug-free) hydrolysis of the nucleotide. Two of the mutations (L976C and F978C) were found to reduce the binding of [γ-32P]-azido-ATP to ABCB1. In contrast, the A980C mutation within TM12 enhanced the rate of ATP hydrolysis; once again, this was due to modified basal activity. Several residues also caused reductions in the potency of stimulation of ATP hydrolysis by nicardipine and vinblastine, although the effects were independent of changes in drug binding per se. Overall, the results indicate that TM12 plays a key role in the progression of the ATP hydrolytic cycle in ABCB1, even in the absence of the transported substrate.
dc.identifier.issn0006-2960
dc.identifier.urihttp://hdl.handle.net/1885/80013
dc.publisherAmerican Chemical Society
dc.sourceBiochemistry
dc.subjectKeywords: ATP hydrolysis; ATP-ase activity; Basal activities; Catalytic cycles; Clinical settings; Cysteine residues; Drug binding; Interdomain communication; Multidrug efflux; Nicardipine; Nucleotide binding; P-glycoprotein; Transmembrane helices; Underlying cause
dc.titleTransmembrane helix 12 modulates progression of the ATP catalytic cycle in ABCB1
dc.typeJournal article
local.bibliographicCitation.issue26
local.bibliographicCitation.lastpage6258
local.bibliographicCitation.startpage6249
local.contributor.affiliationCrowley, Emily, University of Oxford
local.contributor.affiliationO'Mara, Megan, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationReynolds, Catherine, University of Oxford
local.contributor.affiliationTieleman, D. Peter, University of Calgary
local.contributor.affiliationStorm, Janet, University of Oxford
local.contributor.affiliationKerr, Ian, University of Nottingham
local.contributor.affiliationCallaghan, Richard, College of Medicine, Biology and Environment, ANU
local.contributor.authoremailu4022190@anu.edu.au
local.contributor.authoruidO'Mara, Megan, u4022190
local.contributor.authoruidCallaghan, Richard, u5103268
local.description.embargo2037-12-31
local.description.notesImported from ARIES
local.identifier.absfor060112 - Structural Biology (incl. Macromolecular Modelling)
local.identifier.absfor060110 - Receptors and Membrane Biology
local.identifier.absfor060199 - Biochemistry and Cell Biology not elsewhere classified
local.identifier.absseo970106 - Expanding Knowledge in the Biological Sciences
local.identifier.ariespublicationf5625xPUB8353
local.identifier.citationvolume48
local.identifier.doi10.1021/bi900373x
local.identifier.scopusID2-s2.0-67650097355
local.identifier.thomsonID000267609100023
local.identifier.uidSubmittedByf5625
local.type.statusPublished Version

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