NEGATIVELY CHARGED AMINO-ACID-RESIDUES IN THE NICOTINIC RECEPTOR DELTA-SUBUNIT THAT CONTRIBUTE TO THE BINDING OF ACETYLCHOLINE

被引:115
作者
CZAJKOWSKI, C
KAUFMANN, C
KARLIN, A
机构
[1] COLUMBIA UNIV COLL PHYS & SURG, DEPT BIOCHEM & MOLEC BIOPHYS, NEW YORK, NY 10032 USA
[2] COLUMBIA UNIV COLL PHYS & SURG, DEPT PHYSIOL & CELLULAR BIOPHYS, NEW YORK, NY 10032 USA
[3] COLUMBIA UNIV COLL PHYS & SURG, DEPT NEUROL, NEW YORK, NY 10032 USA
关键词
D O I
10.1073/pnas.90.13.6285
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
In nicotinic receptors, the binding sites for acetylcholine are likely to contain negatively charged amino acid side chains that interact with the positively charged quaternary ammonium group of acetylcholine and of other potent agonists. We previously found that a 61-residue segment of the delta subunit contains aspartate or glutamate residues within 1 nm of cysteines in the acetylcholine binding site on the alpha subunit. We have now mutated, one at a time, the 12 aspartates and glutamates in this segment of the mouse muscle delta subunit and have expressed the mutant receptors in Xenopus oocytes. Both the concentration of acetylcholine eliciting half-maximal current (K(app)) and the K(i) for the inhibition by acetylcholine of alpha-bungarotoxin binding were increased 100-fold by the mutation of deltaAsp180 to Asn and 10-fold by the mutation of deltaGlu189 to Gln. These two residues, and their homologs in the gamma and epsilon subunits, are likely to contribute to the acetylcholine binding sites.
引用
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页码:6285 / 6289
页数:5
相关论文
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