Neville L F, Gnatt A, Padan R, Seidman S, Soreq H
Department of Biological Chemistry, Hebrew University of Jerusalem, Israel.
J Biol Chem. 1990 Dec 5;265(34):20735-8.
Structure-function relationships of recombinant human butyrylcholinesterase (CHE) variants were investigated by Xenopus oocyte microinjection. A Ser-425 to Pro-425 mutation failed to modify ligand binding properties. In contrast, Asp-70 to Gly-70 substitution significantly reduced CHE binding capacity for succinylcholine and specific inhibitors, demonstrating Asp-70 as a key anionic site component for certain ligands. Furthermore, the presence of both mutations rendered CHE totally resistant to succinylcholine and dibucaine inhibition, while all mutant proteins bound butyrylthiocholine, benzoylcholine, and propionylcholine normally. These findings imply structural interactions between the conserved Asp-70 and Ser-425 regions in cholinesterases and suggest the contribution of additional electronegative amino acids to anionic site binding.
通过非洲爪蟾卵母细胞显微注射研究了重组人丁酰胆碱酯酶（CHE）变体的结构-功能关系。丝氨酸425突变为脯氨酸425未能改变配体结合特性。相比之下，天冬氨酸70替换为甘氨酸70显著降低了CHE对琥珀酰胆碱和特异性抑制剂的结合能力，表明天冬氨酸70是某些配体的关键阴离子位点组成部分。此外，两种突变同时存在使CHE完全抵抗琥珀酰胆碱和丁卡因的抑制作用，而所有突变蛋白对硫代丁酰胆碱、苯甲酰胆碱和丙酰胆碱的结合正常。这些发现意味着胆碱酯酶中保守的天冬氨酸70和丝氨酸425区域之间存在结构相互作用，并表明其他电负性氨基酸对阴离子位点结合有贡献。
