TY - JOUR
T1 - Adjacent pore-lining residues within sodium channels identified by paired cysteine mutagenesis
AU - Bénitah, Jean Pierre
AU - Tomaselli, Gordon F.
AU - Marban, Eduardo
PY - 1996/7/9
Y1 - 1996/7/9
N2 - The pores of voltage-gated ion channels are lined by protein loops that determine selectivity and conductance. The relative orientations of these 'P' loops remain uncertain, as do the distances between them. Using site-directed mutagenesis, we introduced pairs of cysteines into the P loops of μ1 rat skeletal muscle sodium channels and sought functional evidence of proximity between the substituted residues. Only cysteinyl residues that are in close proximity can form disulfide bonds or metal-chelating sites. The mutant Y401C (domain I) spontaneously formed a disulfide bond when paired with E758C in the P loop of domain II; the same residue, when coupled with G1530C in domain IV, created a high-affinity binding site for Cd2+ ions. The results provide the first specific constraints for intramolecular dimensions of the sodium channel pore.
AB - The pores of voltage-gated ion channels are lined by protein loops that determine selectivity and conductance. The relative orientations of these 'P' loops remain uncertain, as do the distances between them. Using site-directed mutagenesis, we introduced pairs of cysteines into the P loops of μ1 rat skeletal muscle sodium channels and sought functional evidence of proximity between the substituted residues. Only cysteinyl residues that are in close proximity can form disulfide bonds or metal-chelating sites. The mutant Y401C (domain I) spontaneously formed a disulfide bond when paired with E758C in the P loop of domain II; the same residue, when coupled with G1530C in domain IV, created a high-affinity binding site for Cd2+ ions. The results provide the first specific constraints for intramolecular dimensions of the sodium channel pore.
UR - http://www.scopus.com/inward/record.url?scp=0029946602&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029946602&partnerID=8YFLogxK
U2 - 10.1073/pnas.93.14.7392
DO - 10.1073/pnas.93.14.7392
M3 - Article
C2 - 8693004
AN - SCOPUS:0029946602
SN - 0027-8424
VL - 93
SP - 7392
EP - 7396
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 14
ER -