Structures of Enterococcal Glycerol Kinase in the Absence and Presence of Glycerol: Correlation of Conformation to Substrate Binding and a Mechanism of Activation by Phosphorylation
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- 作者：Joanne I. Yeh ; Vé ; ronique Charrier ; Joao Paulo ; Lihui Hou ; Emmanuelle Darbon ; Al Claiborne ; Wim G. J. Hol ; and Josef Deutscher
- 刊名：Biochemistry
- 出版年：2004
- 出版时间：January 20, 2004
- 年：2004
- 卷：43
- 期：2
- 页码：362 - 373
- 全文大小：1570K
- 年卷期：v.43,no.2(January 20, 2004)
- ISSN：1520-4995
文摘
The first structure of a glycerol kinase from a Gram-positive organism, Enterococcuscasseliflavus, has been determined to 2.8 Å resolution in the presence of glycerol and to 2.5 Å resolutionin the absence of substrate. The substrate-induced closure of 7
is significantly smaller than that reportedfor hexokinase, a model for substrate-mediated domain closure that has been proposed for glycerol kinase.Despite the 78% level of sequence identity and conformational similarity in the catalytic cleft regions ofthe En. casseliflavus and Escherichia coli glycerol kinases, remarkable structural differences have nowbeen identified. These differences correlate well with their divergent regulatory schemes of activation byphosphorylation in En. casseliflavus and allosteric inhibition in E. coli. On the basis of our structuralresults, we propose a mechanism by which the phosphorylation of a histidyl residue located 25 Å fromthe active site results in a 10-15-fold increase in the activity of the enterococcal glycerol kinase.
is significantly smaller than that reportedfor hexokinase, a model for substrate-mediated domain closure that has been proposed for glycerol kinase.Despite the 78% level of sequence identity and conformational similarity in the catalytic cleft regions ofthe En. casseliflavus and Escherichia coli glycerol kinases, remarkable structural differences have nowbeen identified. These differences correlate well with their divergent regulatory schemes of activation byphosphorylation in En. casseliflavus and allosteric inhibition in E. coli. On the basis of our structuralresults, we propose a mechanism by which the phosphorylation of a histidyl residue located 25 Å fromthe active site results in a 10-15-fold increase in the activity of the enterococcal glycerol kinase.