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Titolo:
THE SELECTIVITY FILTER OF A POTASSIUM CHANNEL, MURINE KIR2.1, INVESTIGATED USING SCANNING CYSTEINE MUTAGENESIS
Autore:
DART C; LEYLAND ML; SPENCER PJ; STANFIELD PR; SUTCLIFFE MJ;
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 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: 25 - 32
SICI:
0022-3751(1998)511:1<25:TSFOAP>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
INTERNAL TEA BLOCKADE; K+ CHANNEL; SUBUNIT STOICHIOMETRY; SIGNATURE SEQUENCE; ION SELECTIVITY; PORE; MUTATIONS; REGION; EXPRESSION; INHIBITOR;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
36
Recensione:
Indirizzi per estratti:
Citazione:
C. Dart et al., "THE SELECTIVITY FILTER OF A POTASSIUM CHANNEL, MURINE KIR2.1, INVESTIGATED USING SCANNING CYSTEINE MUTAGENESIS", Journal of physiology, 511(1), 1998, pp. 25-32

Abstract

1. We have produced a structural model of the pore-forming H5 (or P) region of the strong inward rectifier K+ channel, Kir2.1, based initially on an existing molecular model of the pore region of the voltage-gated K+ channel, Kv1.3. 2. Cysteine-scanning mutagenesis and subsequent blockage by Ag+ was used to test our model by determining the residues in H5 whose side chains line the ion conduction pathway. 3. Mutations made in eight positions within the highly conserved H5 region resulted in apparent ly non-functional channels. Constructing covalently linked dimers, which carry a cysteine substitution in only one of the linked subunits, rescued six of these mutants; a covalently linked tetramer, carrying a cysteine substitution on only one of the linked subunits, rescued a further mutant. 4. Our results using the dimers and tetramers suggest that residues Thr141, Thr142, Ile143, Tyr145, Phe147 andCys149 are accessible to externally applied Ag+ (100-200 nM) and therefore that their side chains line the channel pore. 5. We conclude that the topology of the Kir pore is similar, but not identical, to that of Kv channels. Additionally, the molecular model suggests that selectivity may be conferred both by aromatic residues (Tyr145 and Phe147) via cation-pi interactions and by backbone carbonyl groups (Thr142 and Gly144).

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/09/20 alle ore 11:29:15