High-affinity Zn block in recombinant N-methyl-D-aspartate receptors with cysteine substitutions at the Q/R/N site

被引:15
作者
Amar, M [1 ]
Perin-Dureau, F [1 ]
Neyton, J [1 ]
机构
[1] Ecole Normale Super, Lab Neurobiol, F-75005 Paris, France
关键词
D O I
10.1016/S0006-3495(01)75684-6
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
In ionotropic glutamate receptors, many channel properties (e.g., selectivity, ion permeation, and ion block) depend on the residue (glutamine, arginine, or asparagine) located at the tip of the pore loop (the Q/R/N site). We substituted a cysteine for the asparagine present at that position in both NR1 and NR2 N-methyl-D-aspartate (NMDA) receptor subunits. Under control conditions, receptors containing mutated NR1 and NR2 subunits show much smaller glutamate responses than wild-type receptors. However, this difference disappears upon addition of heavy metal chelators in the extracellular bath. The presence of cysteines at the Q/R/N site in both subunits of NR1/NR2C receptors results in a 220,000-fold increase in sensitivity of the inhibition by extracellular Zn. In contrast with the high-affinity Zn inhibition of wild-type NR1/NR2A receptors, the high-affinity Zn inhibition of mutated NR1/NR2C receptors shows a voltage dependence, which resembles very much that of the block by extracellular Mg. This indicates that the Zn inhibition of the mutated receptors results from a channel block involving Zn binding to the thiol groups introduced into the selectivity filter. Taking advantage of the slow kinetics of the Zn block, we show that both blocking and unblocking reactions require prior opening of the channel.
引用
收藏
页码:107 / 116
页数:10
相关论文
共 35 条
  • [11] The structure of the potassium channel:: Molecular basis of K+ conduction and selectivity
    Doyle, DA
    Cabral, JM
    Pfuetzner, RA
    Kuo, AL
    Gulbis, JM
    Cohen, SL
    Chait, BT
    MacKinnon, R
    [J]. SCIENCE, 1998, 280 (5360) : 69 - 77
  • [12] Pore stoichiometry of a voltage-gated chloride channel
    Fahlke, C
    Rhodes, TH
    Desai, RR
    George, AL
    [J]. NATURE, 1998, 394 (6694) : 687 - 690
  • [13] GLUSKER JP, 1991, ADV PROTEIN CHEM, V42, P1
  • [14] Hille B., 1992, IONIC CHANNELS EXCIT
  • [15] CLONED GLUTAMATE RECEPTORS
    HOLLMANN, M
    HEINEMANN, S
    [J]. ANNUAL REVIEW OF NEUROSCIENCE, 1994, 17 : 31 - 108
  • [16] Horenstein J, 1998, MOL PHARMACOL, V53, P870
  • [17] BLOCK OF N-METHYL-D-ASPARTATE-ACTIVATED CURRENT BY THE ANTICONVULSANT MK-801 - SELECTIVE BINDING TO OPEN CHANNELS
    HUETTNER, JE
    BEAN, BP
    [J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1988, 85 (04) : 1307 - 1311
  • [18] Structure of the NMDA receptor channel M2 segment inferred from the accessibility of substituted cysteines
    Kuner, T
    Wollmuth, LP
    Karlin, A
    Seeburg, PH
    Sakmann, B
    [J]. NEURON, 1996, 17 (02) : 343 - 352
  • [19] Kuner T, 1996, J NEUROSCI, V16, P3549