Show simple item record Csanády László Mihályi Csaba Szöllősi András Törőcsik Beáta Vergani P 2014-11-04T08:27:53Z 2014-11-04T08:27:53Z 2013
dc.identifier.citation pagination=61-73;journalVolume=142;journalIssueNumber=1;journalTitle=JOURNAL OF GENERAL PHYSIOLOGY; hu
dc.identifier.uri doi:10.1085/jgp.201210954
dc.description.abstract A central step in the gating of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel is the association of its two cytosolic nucleotide-binding domains (NBDs) into a head-to-tail dimer, with two nucleotides bound at the interface. Channel opening and closing, respectively, are coupled to formation and disruption of this tight NBD dimer. CFTR is an asymmetric adenosine triphosphate (ATP)-binding cassette protein in which the two interfacial-binding sites (composite sites 1 and 2) are functionally different. During gating, the canonical, catalytically active nucleotide-binding site (site 2) cycles between dimerized prehydrolytic (state O1), dimerized post-hydrolytic (state O2), and dissociated (state C) forms in a preferential C-->O1-->O2-->C sequence. In contrast, the catalytically inactive nucleotide-binding site (site 1) is believed to remain associated, ATP-bound, for several gating cycles. Here, we have examined the possibility of conformational changes in site 1 during gating, by studying gating effects of perturbations in site 1.Previous work showed that channel closure is slowed, both under hydrolytic and nonhydrolytic conditions, by occupancy of site 1 by N6-(2-phenylethyl)-ATP (P-ATP) as well as by the site-1 mutation H1348A (NBD2 signature sequence). Here, we found that P-ATP prolongs wild-type (WT) CFTR burst durations by selectively slowing (>2x) transition O1-->O2 and decreases the nonhydrolytic closing rate (transition O1-->C) of CFTR mutants K1250A ( approximately 4x) and E1371S ( approximately 3x). Mutation H1348A also slowed ( approximately 3x) the O1-->O2 transition in the WT background and decreased the nonhydrolytic closing rate of both K1250A ( approximately 3x) and E1371S ( approximately 3x) background mutants. Neither P-ATP nor the H1348A mutation affected the 1:1 stoichiometry between ATP occlusion and channel burst events characteristic to WT CFTR gating in ATP. The marked effect that different structural perturbations at site 1 have on both steps O1-->C and O1-->O2 suggests that the overall conformational changes that CFTR undergoes upon opening and coincident with hydrolysis at the active site 2 include significant structural rearrangement at site 1. hu
dc.relation.ispartof urn:issn:0022-1295
dc.title Conformational changes in the catalytically inactive nucleotide-binding site of CFTR. hu
dc.type Journal Article hu 2014-07-17T13:21:58Z
dc.language.rfc3066 en hu
dc.identifier.mtmt 2333381
dc.identifier.wos 000320774000005
dc.identifier.pubmed 23752332
dc.contributor.department SE/ÁOK/I/Orvosi Biokémiai Intézet
dc.contributor.department SE/ÁOK/I/OBI/MTA-SE Lendület Ioncsatorna Kutatócsoport
dc.contributor.institution Semmelweis Egyetem

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