2FEM

Mutant R188M of the Cytidine Monophosphate Kinase From E. Coli

2FEM の概要

• エントリーDOI: 10.2210/pdb2fem/pdb
• 関連するPDBエントリー: 2FEO
• 分子名称: Cytidylate kinase (1 entity in total)
• 機能のキーワード: nucleotide monophosphate kinase; transferase, signaling protein, transferase
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm: P0A6I0
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 24752.34

構造登録者

Ofiteru, A.,Bucurenci, N.,Alexov, E.,Bertrand, T.,Briozzo, P.,Munier-Lehmann, H.,Tourneux, L.,Barzu, O.,Gilles, A.M. (登録日: 2005-12-16, 公開日: 2006-01-10, 最終更新日: 2024-02-14)

主引用文献

Ofiteru, A.,Bucurenci, N.,Alexov, E.,Bertrand, T.,Briozzo, P.,Munier-Lehmann, H.,Gilles, A.M.
Structural and functional consequences of single amino acid substitutions in the pyrimidine base binding pocket of Escherichia coli CMP kinase.
Febs J., 274:3363-3373, 2007

PubMed Abstract: Bacterial CMP kinases are specific for CMP and dCMP, whereas the related eukaryotic NMP kinase phosphorylates CMP and UMP with similar efficiency. To explain these differences in structural terms, we investigated the contribution of four key amino acids interacting with the pyrimidine ring of CMP (Ser36, Asp132, Arg110 and Arg188) to the stability, catalysis and substrate specificity of Escherichia coli CMP kinase. In contrast to eukaryotic UMP/CMP kinases, which interact with the nucleobase via one or two water molecules, bacterial CMP kinase has a narrower NMP-binding pocket and a hydrogen-bonding network involving the pyrimidine moiety specific for the cytosine nucleobase. The side chains of Arg110 and Ser36 cannot establish hydrogen bonds with UMP, and their substitution by hydrophobic amino acids simultaneously affects the K(m) of CMP/dCMP and the k(cat) value. Substitution of Ser for Asp132 results in a moderate decrease in stability without significant changes in K(m) value for CMP and dCMP. Replacement of Arg188 with Met does not affect enzyme stability but dramatically decreases the k(cat)/K(m) ratio compared with wild-type enzyme. This effect might be explained by opening of the enzyme/nucleotide complex, so that the sugar no longer interacts with Asp185. The reaction rate for different modified CMP kinases with ATP as a variable substrate indicated that none of changes induced by these amino acid substitutions was 'propagated' to the ATP subsite. This 'modular' behavior of E. coli CMP kinase is unique in comparison with other NMP kinases.

PubMed: 17542990
DOI: 10.1111/j.1742-4658.2007.05870.x

実験手法

X-RAY DIFFRACTION (1.9 Å)