晶体结构的RNA 3 '末端磷酸环化酶,一种无处不在的酶以不同寻常的拓扑。
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棕榈GJ,比利E, Filipowicz W, Wlodawer
晶体结构的RNA 3 '末端磷酸环化酶,一种无处不在的酶以不同寻常的拓扑。
结构。2000年1月15;8 (1):13-23。
- PubMed ID
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10673421 (在PubMed]
- 文摘
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背景:RNA环化酶是一个家庭的RNA-modifying酶在真核生物中保存,细菌和古生菌。他们促进ATP-dependent转换3 '磷酸的2 ',3 '环磷酸二酯的RNA,涉及反应形成的共价AMP-cyclase中间。这些酶可能是负责生产的环磷酸核糖核酸已知需要很多RNA连接酶的原核生物和真核生物。结果:大肠杆菌的高分辨率结构RNA 3 '末端磷酸环化酶使用多波长反常衍射确定了。两个斜方晶系的晶体形式的大肠杆菌环化酶(空间群P2(1) 2(1) 2(1)和P2(1) 2(1) 2)被用来解决和完善结构2.1决议(R因子20.4%;R(免费的)27.6%)。每个分子RNA的环化酶包括两个领域。大域包含三个重复折叠单元由两个平行的α螺旋和β四股表;这个折叠以前在翻译起始因子3 (IF3)。大域相似的两个域之一5-enolpyruvylshikimate-3-phosphate合成酶和UDP-N-acetylglucosamine enolpyruvyl转移酶。 The smaller domain uses a similar secondary structure element with different topology, observed in many other proteins such as thioredoxin. CONCLUSIONS: The fold of RNA cyclase consists of known elements connected in a new and unique manner. Although the active site of this enzyme could not be unambiguously assigned, it can be mapped to a region surrounding His309, an adenylate acceptor, in which a number of amino acids are highly conserved in the enzyme from different sources. The structure of E. coli cyclase will be useful for interpretation of structural and mechanistic features of this and other related enzymes.