MEMBRANE INTERACTIONS OF THE SODIUM-CHANNEL S4 SEGMENT AND ITS FLUORESCENTLY-LABELED ANALOGS

被引:24
作者
RAPAPORT, D [1 ]
DANIN, M [1 ]
GAZIT, E [1 ]
SHAI, Y [1 ]
机构
[1] WEIZMANN INST SCI, DEPT MEMBRANE RES & BIOPHYS, IL-76100 REHOVOT, ISRAEL
关键词
D O I
10.1021/bi00152a025
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
A 24-amino acid peptide corresponding to the S4 segment of the sodium channel was synthesized. In order to perform fluorescence energy transfer measurements and to monitor the interaction of the peptide with lipid vesicles, the peptide was selectively labeled with fluorescence probes at either its N- or C-terminal amino acids. The fluorescent emission spectra of 7-nitrobenz-2-oxa-1,3-diazol-4-yl-(NBD-)labeled analogues displayed blue shifts upon binding to small unilamellar vesicles (SUV), reflecting the relocation of the fluorescent probe to an environment of increased apolarity. The results revealed that both the N- and C-terminus of the S4 segment are located within the lipid bilayer. Titration of solutions containing NBD-labeled peptides with SUV was used to generate binding isotherms, from which surface partition constants, in the range of 10(4) M-1, Were derived. The shape of the binding isotherms as well as fluorescence energy transfer measurements suggest that aggregation of peptide monomers within the membrane readily occurs in acidic but not in zwitterionic vesicles. Furthermore, the results provide good correlation between the incidence of aggregation in PC/PS vesicles and the ability of the peptides to permeate the vesicle's membrane. However, a transmembrane diffusion potential had no detectable effect on the location of the peptide within the lipid bilayer or on its aggregation state. Taken together, these results provide experimental support for a transmembranal localization for the sodium channel S4 segment as well as for its potential in forming part of the channel's lining, both properties in agreement with the "propagating helix" model, suggested by Guy and Conti [Guy, H. R., & Conti, F. (1990) Trends Neurosci. 13, 201-206].
引用
收藏
页码:8868 / 8875
页数:8
相关论文
共 43 条
[1]   SERUM-INDUCED LEAKAGE OF LIPOSOME CONTENTS [J].
ALLEN, TM ;
CLELAND, LG .
BIOCHIMICA ET BIOPHYSICA ACTA, 1980, 597 (02) :418-426
[2]   A NEUTRAL AMINO-ACID CHANGE IN SEGMENT-IIS4 DRAMATICALLY ALTERS THE GATING PROPERTIES OF THE VOLTAGE-DEPENDENT SODIUM-CHANNEL [J].
AULD, VJ ;
GOLDIN, AL ;
KRAFTE, DS ;
CATTERALL, WA ;
LESTER, HA ;
DAVIDSON, N ;
DUNN, RJ .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1990, 87 (01) :323-327
[3]  
Barlett G.R., 1959, J BIOL CHEM, V234, P466
[4]   MELITTIN BINDING TO MIXED PHOSPHATIDYLGLYCEROL PHOSPHATIDYLCHOLINE MEMBRANES [J].
BESCHIASCHVILI, G ;
SEELIG, J .
BIOCHEMISTRY, 1990, 29 (01) :52-58
[5]   VOLTAGE-DEPENDENT GATING OF SODIUM-CHANNELS - CORRELATING STRUCTURE AND FUNCTION [J].
CATTERALL, WA .
TRENDS IN NEUROSCIENCES, 1986, 9 (01) :7-10
[6]   PARALLAX METHOD FOR DIRECT MEASUREMENT OF MEMBRANE PENETRATION DEPTH UTILIZING FLUORESCENCE QUENCHING BY SPIN-LABELED PHOSPHOLIPIDS [J].
CHATTOPADHYAY, A ;
LONDON, E .
BIOCHEMISTRY, 1987, 26 (01) :39-45
[7]   SURFACE DENSITY DETERMINATION IN MEMBRANES BY FLUORESCENCE ENERGY-TRANSFER [J].
FUNG, BKK ;
STRYER, L .
BIOCHEMISTRY, 1978, 17 (24) :5241-5248
[8]   ION CHANNELS FORMED BY A HIGHLY CHARGED PEPTIDE [J].
GHOSH, P ;
STROUD, RM .
BIOCHEMISTRY, 1991, 30 (14) :3551-3557
[9]   THE STRUCTURE OF THE VOLTAGE-SENSITIVE SODIUM-CHANNEL - INFERENCES DERIVED FROM COMPUTER-AIDED ANALYSIS OF THE ELECTROPHORUS-ELECTRICUS CHANNEL PRIMARY STRUCTURE [J].
GREENBLATT, RE ;
BLATT, Y ;
MONTAL, M .
FEBS LETTERS, 1985, 193 (02) :125-134
[10]  
GUY HR, 1988, CURR TOP MEMBR TRANS, V33, P289