Characterization of a recombinant type II 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase from Helicobacter pylori.

Webby, Celia J., Patchett, Mark L. and Parker, Emily J. (2005) Characterization of a recombinant type II 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase from Helicobacter pylori.. Biochemical Journal, 390 1: 223-230. doi:10.1042/BJ20050259


Author Webby, Celia J.
Patchett, Mark L.
Parker, Emily J.
Title Characterization of a recombinant type II 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase from Helicobacter pylori.
Journal name Biochemical Journal   Check publisher's open access policy
ISSN 0264-6021
1470-8728
Publication date 2005-08
Sub-type Article (original research)
DOI 10.1042/BJ20050259
Volume 390
Issue 1
Start page 223
End page 230
Total pages 8
Place of publication London, United Kingdom
Publisher Portland Press
Language eng
Formatted abstract
DAH7P (3-Deoxy-D-arabino-heptulosonate 7-phosphate) synthase catalyses the condensation reaction between phosphoenolpyruvate (PEP) and D-erythrose 4-phosphate (E4P) as the first committed step in the biosynthesis of aromatic compounds in plants and micro-organisms. Previous work has identified two families of DAH7P synthases based on sequence similarity and molecular mass, with the majority of the mechanistic and structural studies being carried out on the type I paralogues from Escherichia coli. Whereas a number of organisms possess genes encoding both type I and type II DAH7P synthases, the pathogen Helicobacter pylori has only a single, type II, enzyme. Recombinant DAH7P synthase from H. pylori was partially solubilized by co-expression with chaperonins GroEL/GroES in E. coli, and purified to homogeneity. The enzyme reaction follows an ordered sequential mechanism with the following kinetic parameters: Km (PEP), 3 µM; Km (E4P), 6 µM; and kcat, 3.3 s-1. The enzyme reaction involves interaction of the si face of PEP with the re face of E4P. H. pylori DAH7P synthase is not inhibited by phenylalanine, tyrosine, tryptophan or chorismate. EDTA inactivates the enzyme, and activity is restored by a range of bivalent metal ions, including (in order of decreasing effectiveness) Co2+, Mn2+, Ca2+, Mg2+, Cu2+ and Zn2+. Analysis of type II DAH7P synthase sequences reveals several highly conserved motifs, and comparison with the type I enzymes suggests that catalysis by these two enzyme types occurs on a similar active-site scaffold and that the two DAH7P synthase families may indeed be distantly related.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Faculty of Health and Behavioural Sciences -- Publications
ERA 2012 Admin Only
 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 14 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 14 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Sun, 30 Oct 2011, 10:32:02 EST by Celia Webby on behalf of Faculty Of Health Sciences