The influence of surface charges on the conductance of the human connexin37 gap junction channel.
Biophys J
; 78(2): 752-60, 2000 Feb.
Article
en En
| MEDLINE
| ID: mdl-10653788
The single-channel conductance of the hCx37 homotypic gap junction channel does not saturate with transjunctional voltages up to +/-75 mV, nor does it depend linearly on the intracellular electrolyte concentration. The average maximum unitary conductances measured in KCl were 175 pS (30 mM), 236 pS (55 mM), 343 pS (110 mM), and 588 pS (270 mM) in the presence of 0.1 mM MgCl(2). The unexpectedly high unitary conductance at low salt concentrations can be explained by fixed charge groups within or near the channel orifice. Fixed cytoplasmic surface charges (3.4 e) positioned adjacent (15 A) to the channel pore adequately model the data (surface charge density of 0.24 e/(nm)(2)). In other experiments, high Mg(2+) reduced the unitary conductance of hCx37 homotypic gap junction channels more than predicted by screening alone, consistent with specific effects of Mg(2+) on the channel.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Uniones Comunicantes
/
Conexinas
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Biophys J
Año:
2000
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos