Role of proline residue in the channel-forming and catecholamine-releasing activities of the peptaibol, trichosporin-B-VIa.
Biochim Biophys Acta
; 1283(1): 31-6, 1996 Aug 14.
Article
em En
| MEDLINE
| ID: mdl-8765091
ABSTRACT
Trichosporin-B-VIa (TS-B-VIa) has a Pro14-kinked helical structure which is considered to be important for the formation of peptaibol-type ion-channels in lipid bilayer membranes. TS-B-VIa and its analog [Aib14]TS-B-VIa with Pro-->Aib substitution at position 14, resulting in a straight helical structure, were tested for ion-channel-forming activity in planar lipid bilayer membranes and for ability to induce catecholamine secretion from cultured bovine adrenal chromaffin cells. Voltage-dependent multi-channel conductance, which is characteristic of TS-B-VIa, was also observed for [Aib14]TS-B-VIa. In single-channel measurements, current fluctuations induced by [Aib14]TS-B-VIa had a shorter life-time and showed fewer substates than those induced by TS-B-VIa. Catecholamine secretion induced by these peptides at low concentrations is completely Ca(2+)-dependent. At high concentrations, TS-B-VIa-induced secretion was partly independent of external Ca2+, but this was not the case for the analog. The differences of behavior can be explained in terms of the differences of hydrophobicity, and magnitude of dipole moment due to the conformational changes around position 14 and the C-terminal domain caused by the Pro-->Aib substitution.
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Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Prolina
/
Catecolaminas
/
Canais Iônicos
/
Antibacterianos
Limite:
Animals
Idioma:
En
Revista:
Biochim Biophys Acta
Ano de publicação:
1996
Tipo de documento:
Article
País de afiliação:
Japão