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Titolo:
THE DEPENDENCE OF AG+ BLOCK OF A POTASSIUM CHANNEL, MURINE KIR2.1, ONA CYSTEINE RESIDUE IN THE SELECTIVITY FILTER
Autore:
DART C; LEYLAND ML; BARRETTJOLLEY R; SHELTON PA; SPENCER PJ; CONLEY EC; SUTCLIFFE MJ; STANFIELD PR;
Indirizzi:
UNIV LEICESTER,DEPT CELL PHYSIOL & PHARMACOL,ION CHANNEL GRP,POB 138 LEICESTER LE1 9HN LEICS ENGLAND UNIV LEICESTER,DEPT CELL PHYSIOL & PHARMACOL,ION CHANNEL GRP LEICESTER LE1 9HN LEICS ENGLAND UNIV LEICESTER,DEPT BIOCHEM LEICESTER LE1 9HN LEICS ENGLAND UNIV LEICESTER,DEPT PATHOL LEICESTER LE1 9HN LEICS ENGLAND UNIV LEICESTER,DEPT CHEM LEICESTER LE1 9HN LEICS ENGLAND UNIV LEICESTER,CTR MECHANISMS HUMAN TOXIC LEICESTER LE1 9HN LEICS ENGLAND
Titolo Testata:
Journal of physiology
fascicolo: 1, volume: 511, anno: 1998,
pagine: 15 - 24
SICI:
0022-3751(1998)511:1<15:TDOABO>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
RECTIFIER K+ CHANNELS; SUBUNIT STOICHIOMETRY; FUNCTIONAL EXPRESSION; BINDING-SITE; PORE; ION; CONDUCTANCE; SPERMINE; CLONING; VOLTAGE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
33
Recensione:
Indirizzi per estratti:
Citazione:
C. Dart et al., "THE DEPENDENCE OF AG+ BLOCK OF A POTASSIUM CHANNEL, MURINE KIR2.1, ONA CYSTEINE RESIDUE IN THE SELECTIVITY FILTER", Journal of physiology, 511(1), 1998, pp. 15-24

Abstract

1. Externally applied Ag+ (100-200 nM) irreversibly blocked the strong inwardly rectifying K+ channel, Kir2.1. 2. Mutation to serine of a cysteine residue at position 149 in the pore-forming H5 region of Kir2.1 abolished Ag+ blockage. 3. To determine how many of the binding sites must be occupied by Ag+ before the channel is blocked, we measured the rate of channel block and found that our results were best fitted assuming that only one Ag+ ion need bind to eliminate channel current. 4. We tested our hypothesis further by constructing covalently linked dimers and tetramers of Kir2.1 in which cysteine had been replaced by serine in one (dimer) or three (tetramer) of the linked subunits. Whenexpressed, these constructs yielded functional channels with either two (dimer) or one (tetramer) cysteines per channel at position 149. 5. Blockage in the tetramer was complete after sufficient exposure to 200 nM Ag+, a result that is also consistent with only one Ag+ being required to bind to Cys149 to block fully. The rate of development of blockage was 16 times slower than in wild-type channels; the rate was 4 times slower in channels formed from dimers.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 23/09/20 alle ore 09:37:22