2cmk
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(New page: 200px<br /><applet load="2cmk" size="450" color="white" frame="true" align="right" spinBox="true" caption="2cmk, resolution 2.0Å" /> '''CYTIDINE MONOPHOSPHAT...)
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Revision as of 07:03, 21 November 2007
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CYTIDINE MONOPHOSPHATE KINASE IN COMPLEX WITH CYTIDINE-DI-PHOSPHATE
Overview
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 A resolution. The structure of the enzyme, in complex with CDP was determined at 2.0 A resolution. Like other NMP, kinases, the protein contains a central parallel beta sheet, the strands, of which are connected by alpha helices. 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.
About this Structure
2CMK is a Single protein structure of sequence from Escherichia coli with SO4 and CDP as ligands. Active as Cytidylate kinase, with EC number 2.7.4.14 Full crystallographic information is available from OCA.
Reference
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., Briozzo P, Golinelli-Pimpaneau B, Gilles AM, Gaucher JF, Burlacu-Miron S, Sakamoto H, Janin J, Barzu O, Structure. 1998 Dec 15;6(12):1517-27. PMID:9862805
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