人类乙酰胆碱酯酶的突变。识别残留参与催化活性多肽折叠。
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珂容曼Shafferman A, C, Flashner Y,莱特纳M, Grosfeld H, Ordentlich,沙丘状积砂Y,科恩年代,爱丽儿N,巴拉克D, et al。
人类乙酰胆碱酯酶的突变。识别残留参与催化活性多肽折叠。
生物化学杂志。1992年9月5日;267 (25):17640 - 8。
- PubMed ID
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1517212 (在PubMed]
- 文摘
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证据的介入ser - 203, - 447, glu - 334在人类乙酰胆碱酯酶的催化三分子提供的替换这些氨基酸的丙氨酸残基。20个氨基酸突变位置到目前为止在人类乙酰胆碱酯酶(疼痛),这三个在废除检测酶活性独特的野生型(小于0.0003),然而,允许适当的生产、折叠和分泌。这是第一生化证据谷氨酸在水解酶的参与三合会(施拉格,法学博士李,Y。吴,M。,Cygler自然m(1991) 351年,761 - 764),支持x射线晶体结构数据的鱼雷californica乙酰胆碱酯酶(苏斯曼J.L.Harel, M。Frolow F。Oefner C。高盛,。、可能性、l和Silman,即科学(1991)253年,872 - 879)。试图把疼痛三合会转换成由定点诱变Cys-His-Glu或Ser-His-Asp配置没有产生有效的疼痛活动。另一种类型的替代,asp - 74 g或Asn,生成一个活跃的酶和琥珀酰胆碱和dibucaine阻力增加;因此模仿在疼痛的分子表型的非典型butyrylcholinesterase自然变异(D70G突变)。 Mutations of other carboxylic residues Glu-84, Asp-95, Asp-333, and Asp-349, all conserved among cholinesterases, did not result in detectable alteration in the recombinant AChE, although polypeptide productivity of the D95N mutant was considerably lower. In contrast, complete absence of secreted human AChE polypeptide was observed when Asp-175 or Asp-404 were substituted by Asn. These two aspartates are conserved in the entire cholinesterase/thyroglobulin family and appear to play a role in generating and/or maintaining the folded state of the polypeptide. The x-ray structure of the Torpedo acetylcholinesterase supports this assumption by revealing the participation of these residues in salt bridges between neighboring secondary structure elements.