Structures of Escherichia coli CMP kinase alone and in complex with CDP:: a new fold of the nucleoside monophosphate binding domain and insights into cytosine nucleotide specificity
Structures of Escherichia coli CMP kinase alone and in complex with CDP:: a new fold of the nucleoside monophosphate binding domain and insights into cytosine nucleotide specificity
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DOI：
10.1016/s0969-2126(98)00150-6
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发表时间：
1998-12-15
期刊：
影响因子：
5.7
通讯作者：
Bârzu, O
中科院分区：
文献类型：
--
作者：
Briozzo, P;Golinelli-Pimpaneau, B;Bârzu, O
背景资料：核苷单磷酸激酶（NMP激酶）催化磷酰基从核苷三磷酸到核苷单磷酸的可逆转移。其中，大肠杆菌胞苷一磷酸激酶（cytidine monophosphate kinase，CMP）具有显著的特异性，它对CMP具有特异性，而在真核生物中，一种独特的UMP/CMP激酶以相似的效率磷酸化CMP和UMP。大肠杆菌通过单一同晶置换解析，并以1.75埃分辨率精细化。在2.0埃分辨率下测定与CDP复合的酶的结构。与其他NMP激酶一样，该蛋白含有一个中央平行β折叠，其链通过α hetices连接。该酶与其他NMP激酶的不同之处在于存在位于NMP结合（NMPbind）结构域中的40个残基插入物。该插入片段包含两个结构域：一个包含一个三链反平行β折叠，另一个包含两个α螺旋。在已知结构的其他NMP激酶中没有等价物。首先，大的NMPbind插入物经历CDP诱导的重排：其β折叠结构域远离底物，而其螺旋结构域以可能改善活性位点保护的运动靠近它。其次，参与CDP识别的残基在CMP激酶中是保守的，并且在其他NMP激酶中没有对应物。这里提出的结构是一个新的家族的NMP激酶特异性CMP。
Background: Nucleoside monophosphate kinases (NMP kinases) catalyze the reversible transfer of a phosphoryl group from a nucleoside triphosphate to a nucleoside monophosphate. Among them, cytidine monophosphate kinase from Escherichia coli has a striking particularity: it is specific for CMP, whereas in eukaryotes a unique UMP/CMP kinase phosphorylates both CMP and UMP with similar efficiency.Results: The crystal structure of the CMP kinase apoenzyme from E. coli was solved by single isomorphous replacement and refined at 1.75 Angstrom resolution. The structure of the enzyme in complex with CDP was determined at 2.0 Angstrom resolution. Like other NMP kinases, the protein contains a central parallel beta sheet, the strands of which are connected by alpha hetices. The enzyme differs from other NMP kinases in the presence of a 40-residue insert situated in the NMP-binding (NMPbind) domain. This insert contains two domains: one comprising a three-stranded antiparallel beta sheet, the other comprising two alpha helices,Conclusions: Two features of the CMP kinase from E. coli have no equivalent in other NMP kinases of known structure. Firstly, the large NMPbind insert undergoes a CDP-induced rearrangement: its beta-sheet domain moves away from the substrate, whereas its helical domain comes closer to it in a motion likely to improve the protection of the active site, Secondly, residues involved in CDP recognition are conserved in CMP kinases and have no counterpart in other NMP kinases. The structures presented here are the first of a new family of NMP kinases specific for CMP.