Document Detail

Structure of Escherichia coli ribokinase in complex with ribose and dinucleotide determined to 1.8 A resolution: insights into a new family of kinase structures.
MedLine Citation:
PMID:  9519409     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: D-ribose must be phosphorylated at O5' before it can be used in either anabolism or catabolism. This reaction is catalysed by ribokinase and requires the presence of ATP and magnesium. Ribokinase is a member of a family of carbohydrate kinases of previously unknown structure. RESULTS: The crystal structure of ribokinase from Escherichia coli in complex with ribose and dinucleotide was determined at 1.84 A resolution by multiple isomorphous replacement. There is one 33 kDa monomer of ribokinase in the asymmetric unit but the protein forms a dimer around a crystallographic twofold axis. Each subunit consists of a central alpha/beta unit, with a new type of nucleotide-binding fold, and a distinct beta sheet that forms a lid over the ribose-binding site. Contact between subunits involves orthogonal packing of beta sheets, in a novel dimer interaction that we call a beta clasp. CONCLUSIONS: Inspection of the complex indicates that ribokinase utilises both a catalytic base for activation of the ribose in nucleophilic attack and an anion hole that stabilises the transition state during phosphoryl transfer. The structure suggests an ordered reaction mechanism, similar to those proposed for other carbohydrate kinases that probably involves conformational changes. We propose that the beta-clasp structure acts as a lid, closing and opening upon binding and release of ribose. From these observations, an understanding of the structure and catalytic mechanism of related sugar kinases can be obtained.
J A Sigrell; A D Cameron; T A Jones; S L Mowbray
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Structure (London, England : 1993)     Volume:  6     ISSN:  0969-2126     ISO Abbreviation:  Structure     Publication Date:  1998 Feb 
Date Detail:
Created Date:  1998-05-07     Completed Date:  1998-05-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101087697     Medline TA:  Structure     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  183-93     Citation Subset:  IM    
Department of Molecular Biology, Uppsala University, Sweden.
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MeSH Terms
Adenylyl Imidodiphosphate / chemistry*
Amino Acid Sequence
Binding Sites
Crystallography, X-Ray
Escherichia coli / enzymology*
Models, Molecular
Molecular Sequence Data
Phosphotransferases (Alcohol Group Acceptor) / chemistry*
Protein Conformation*
Protein Structure, Secondary
Ribose / chemistry*
Sequence Alignment
Reg. No./Substance:
25612-73-1/Adenylyl Imidodiphosphate; 50-69-1/Ribose; EC 2.7.1.-/Phosphotransferases (Alcohol Group Acceptor); EC

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