Charge at the lidocaine binding site residue Phe-1759 affects permeation in human cardiac voltage-gated sodium channels

被引:60
作者
McNulty, Megan M.
Edgerton, Gabrielle B.
Shah, Ravi D.
Hanck, Dorothy A.
Fozzard, Harry A.
Lipkind, Gregory M.
机构
[1] Univ Chicago, Cardiac Electrophysiol Lab, Dept Med, Chicago, IL 60637 USA
[2] Univ Chicago, Comm Neurobiol, Chicago, IL 60637 USA
来源
JOURNAL OF PHYSIOLOGY-LONDON | 2007年 / 581卷 / 02期
关键词
D O I
10.1113/jphysiol.2007.130161
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Our homology molecular model of the open/inactivated state of the Na+ channel pore predicts, based on extensive mutagenesis data, that the local anaesthetic lidocaine docks eccentrically below the selectivity filter, such that physical occlusion is incomplete. Electrostatic field calculations suggest that the drug's positively charged amine produces an electrostatic barrier to permeation. To test the effect of charge at this pore level on permeation in hNa(V)1.5 we replaced Phe-1759 of domain IVS6, the putative binding site for lidocaine's alkylamino end, with positively and negatively charged residues as well as the neutral cysteine and alanine. These mutations eliminated use-dependent lidocaine block with no effect on tonic/rested state block. Mutant whole cell currents were kinetically similar to wild type (WT). Single channel conductance (gamma) was reduced from WT in both F1759K (by 38%) and F1759R (by 18%). The negatively charged mutant F1759E increased gamma by 14%, as expected if the charge effect were electrostatic, although F1759D was like WT. None of the charged mutations affected Na+/K+ selectivity. Calculation of difference electrostatic fields in the pore model predicted that lidocaine produced the largest positive electrostatic barrier, followed by lysine and arginine, respectively. Negatively charged glutamate and aspartate both lowered the barrier, with glutamate being more effective. Experimental data were in rank order agreement with the predicted changes in the energy profile. These results demonstrate that permeation rate is sensitive to the inner pore electrostatic field, and they are consistent with creation of an electrostatic barrier to ion permeation by lidocaine's charge.
引用
收藏
页码:741 / 755
页数:15
相关论文
共 54 条
[41]   A MUTANT OF TTX-RESISTANT CARDIAC SODIUM-CHANNELS WITH TTX-SENSITIVE PROPERTIES [J].
SATIN, J ;
KYLE, JW ;
CHEN, M ;
BELL, P ;
CRIBBS, LL ;
FOZZARD, HA ;
ROGART, RB .
SCIENCE, 1992, 256 (5060) :1202-1205
[42]   Pore properties of rat brain II sodium channels mutated in the selectivity filter domain [J].
Schlief, T ;
Schonherr, R ;
Imoto, K ;
Heinemann, SH .
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS, 1996, 25 (02) :75-91
[43]   LOCAL-ANESTHETICS - EFFECT OF PH ON USE-DEPENDENT BLOCK OF SODIUM CHANNELS IN FROG MUSCLE [J].
SCHWARZ, W ;
PALADE, PT ;
HILLE, B .
BIOPHYSICAL JOURNAL, 1977, 20 (03) :343-368
[44]   Accessibility of mid-segment domain IVS6 residues of the voltage-gated Na+ channel to methanethiosulfonate reagents [J].
Sunami, A ;
Tracey, A ;
Glaaser, IW ;
Lipkind, GM ;
Hanck, DA ;
Fozzard, HA .
JOURNAL OF PHYSIOLOGY-LONDON, 2004, 561 (02) :403-413
[45]   Sodium channel selectivity filter regulates antiarrhythmic drug binding [J].
Sunami, A ;
Dudley, SC ;
Fozzard, HA .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1997, 94 (25) :14126-14131
[46]   Altered ionic selectivity of the sodium channel revealed by cysteine mutations within the pore [J].
Tsushima, RG ;
Li, RA ;
Backx, PH .
JOURNAL OF GENERAL PHYSIOLOGY, 1997, 109 (04) :463-475
[47]   Rapid and slow voltage-dependent conformational changes in segment IVS6 of voltage-gated Na+ channels [J].
Vedantham, V ;
Cannon, SC .
BIOPHYSICAL JOURNAL, 2000, 78 (06) :2943-2958
[48]  
Wang GK, 1998, PFLUG ARCH EUR J PHY, V435, P293
[49]   Disparate role of Na+ channel D2-S6 residues in batrachotoxin and local anesthetic action [J].
Wang, SY ;
Barile, M ;
Wang, GK .
MOLECULAR PHARMACOLOGY, 2001, 59 (05) :1100-1107
[50]  
Wright SN, 1998, MOL PHARMACOL, V54, P733