FEBS Letters | |
Extracellular proton alters the divalent cation binding affinity in a cyclic nucleotide‐gated channel pore | |
Park, Chul-Seung1  Rho, Seong-Hwan1  | |
[1] Department of Life Science, Kwangju Institute of Science and Technology (K-JIST), 572 Sangam-dong, Kwangsan-Ku, Kwangju 506-712, South Korea | |
关键词: Extracellular proton; Cyclic nucleotide-gated channel; Binding affinity; Glutamate residue; CNG; cyclic nucleotide-gated; cGMP; guanosine 3′; 5′-cyclic mononucleotide; P-region; pore-forming region; Asp; aspartate; Glu; glutamate; Gly; glycine; | |
DOI : 10.1016/S0014-5793(98)01353-2 | |
学科分类:生物化学/生物物理 | |
来源: John Wiley & Sons Ltd. | |
【 摘 要 】
Extracellular protons in the range of 10−9 to 10−5 M effectively suppressed Na+ current (K 1/2=10−6.1) through the bovine retinal guanosine 3′,5′-cyclic mononucleotide-gated ion channel expressed in Xenopus oocytes. The reduction of channel current was mediated by a single glutamate residue (Glu363) within the pore-forming region of the channel, also involved in extracellular divalent cation binding. Increasing the concentration of extracellular proton decreased the binding affinity of the extracellular divalent cation (e.g. Sr2+) and the large difference of binding affinity previously observed between the wild-type and E363D mutant channel disappeared. These results indicate that the permeation characteristics of cyclic nucleotide-gated ion channel can be altered by extracellular pH through a single acidic residue in the channel conduction pathway.
【 授权许可】
Unknown
【 预 览 】
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