Involvement of different S parts in the voltage dependency of Na channel gating.

Autor: Kra-Oz, Zipora, Spira, Gad, Palti, Yoram, Meiri, Hamutal
Zdroj: Journal of Membrane Biology; 1992, Vol. 129 Issue 2, p189-198, 10p
Abstrakt: Three synthetic peptides corresponding to parts of S of the first repeat of eel electroplax sodium channel were synthesized. The basic peptide was Cwhich corresponds to amino acids 210-223 (eel channel numbering) and two subfractions: an external fraction, C(amino acid 210-217); and an internal part, C(amino acid 218-221). Peptide Cincludes four of the charged amino acids of this domain; peptide Cincludes three of the charged amino acids and is closer to the external membrane surface (according to channel models) than peptide Cwhich includes the fourth charged amino acid alone. Antibodies generated in rabbits against these peptides were shown to be site specific. Using the whole-cell patch-clamp technique, we found that in rat dorsal root ganglion (DRG) cells, the antibodies against Cbut not against Chad an effect on the gating parameters. They shifted the Na-channel inactivation curve towards hyperpolarization and decreased the slope of the Na-channel activation curve. These results demonstrate that during the conformational changes associated with channel gating, the fourth charged amino acid of S must be accessible to antibodies given to the external solution. Furthermore, they indicate a specific involvement of S in the voltage dependency of the gating processes. This study was supported by a basic research grant of The Israel Academy of Sciences and Humanities (#430.87 to H.M. and G.S.). [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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