Structural determinants of ion selectivity in brain calcium channel

FEBS Letters

Kim, Man-Suk³  Morii, Takashi¹  Imoto, Keiji²  Sun, Li-Xin²  Mori, Yasuo² 

[1] Department of Polymer Science and Engineering, Kyoto Institute of Technology, Kyoto 606, Japan;Departments of Medical Chemistry and Molecular Genetics, Kyoto University Faculty of Medicine, Kyoto 606-01, Japan;Third Department of Internal Medicine, Kyoto University Faculty of Medicine, Kyoto 606-01, Japan

关键词: Calcium channel;    Site-directed mutagenesis;    cDNA expression;    Ion selectivity;    Inorganic blocker;   

DOI  :  10.1016/0014-5793(93)80009-J

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Glutamic acid residues in the SS2 segment of the internal repeats III and IV of the brain calcium channel BI were subjected to single point mutations. The mutant channels were tested for macroscopic current properties and sensitivities to inorganic blockers. The mutation that replaces glutamic acid 1,469 with glutamine altered ion-selection properties and strongly reduced the sensitivity to Cd²⁺, whereas the analogous mutation of glutamic acid 1,765 exerted smaller effects on ion-selection properties. Our results indicate that these glutamic acid residues, equivalently positioned in the aligned sequences, play different roles in the selective permeability of the calcium channel.

【 授权许可】

Unknown