TY - JOUR
T1 - Interaction of local anesthetics with a peptide encompassing the IV/S4-S5 linker of the Na+ channel
AU - Fraceto, Leonardo F.
AU - Oyama, Sérgio
AU - Nakaie, Clóvis R.
AU - Spisni, Alberto
AU - de Paula, Eneida
AU - Pertinhez, Thelma A.
PY - 2006/8/20
Y1 - 2006/8/20
N2 - The peptide pIV/S4-S5 encompasses the cytoplasmic linker between helices S4-S5 in domain IV of the voltage-gated Na+ channel, residues 1644-1664.22Residues numbering correspond to the primary sequence of the voltage-gated human brain Na+ channel [1]. The interaction of two local anesthetics (LA), lidocaine and benzocaine, with pIV/S4-S5 has been studied by DOSY, heteronuclear NMR 1H-15N-HSQC spectroscopy and computational methods. DOSY indicates that benzocaine, a neutral ester, exhibits stronger interaction with pIV/S4-S5 than lidocaine, a charged amine-amide. Weighted average chemical shifts, Δδ(1H-15N), show that benzocaine affects residues L1653, M1655 and S1656 while lidocaine slightly perturbs residues I1646, L1649 and A1659, L1660, near the N- and C-terminus, respectively. Computational methods confirmed the stability of the benzocaine binding and the existence of two binding sites for lidocaine. Even considering that the approach of studying the peptide in the presence of a co-solvent (TFE/H2O, 30%/70% v/v) has an inherently limited implication, our data strongly support the existence of multiple LA binding sites in the IV/S4-S5 linker, as suggested in the literature. In addition, we consider that LA can bind to the S4-S5 linker with diverse binding modes and strength since this linker is part of the receptor for the "inactivation gate particle". Conditions for devising new functional studies, aiming to better understand Na+ channel functionality as well as the various facets of LA pharmacological activity are proposed in this work.
AB - The peptide pIV/S4-S5 encompasses the cytoplasmic linker between helices S4-S5 in domain IV of the voltage-gated Na+ channel, residues 1644-1664.22Residues numbering correspond to the primary sequence of the voltage-gated human brain Na+ channel [1]. The interaction of two local anesthetics (LA), lidocaine and benzocaine, with pIV/S4-S5 has been studied by DOSY, heteronuclear NMR 1H-15N-HSQC spectroscopy and computational methods. DOSY indicates that benzocaine, a neutral ester, exhibits stronger interaction with pIV/S4-S5 than lidocaine, a charged amine-amide. Weighted average chemical shifts, Δδ(1H-15N), show that benzocaine affects residues L1653, M1655 and S1656 while lidocaine slightly perturbs residues I1646, L1649 and A1659, L1660, near the N- and C-terminus, respectively. Computational methods confirmed the stability of the benzocaine binding and the existence of two binding sites for lidocaine. Even considering that the approach of studying the peptide in the presence of a co-solvent (TFE/H2O, 30%/70% v/v) has an inherently limited implication, our data strongly support the existence of multiple LA binding sites in the IV/S4-S5 linker, as suggested in the literature. In addition, we consider that LA can bind to the S4-S5 linker with diverse binding modes and strength since this linker is part of the receptor for the "inactivation gate particle". Conditions for devising new functional studies, aiming to better understand Na+ channel functionality as well as the various facets of LA pharmacological activity are proposed in this work.
KW - Benzocaine
KW - Lidocaine
KW - Local anesthetics
KW - Nuclear magnetic resonance
KW - Peptide
KW - Voltage-gated sodium channel
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U2 - 10.1016/j.bpc.2006.03.010
DO - 10.1016/j.bpc.2006.03.010
M3 - Article
C2 - 16687202
AN - SCOPUS:33746930241
VL - 123
SP - 29
EP - 39
JO - Biophysical Chemistry
JF - Biophysical Chemistry
SN - 0301-4622
IS - 1
ER -