DHDPS (dihydrodipicolinate synthase) catalyses the branch point in lysine biosynthesis in bacteria and plants and is feedback inhibited by lysine. DHDPS from the thermophilic bacterium Thermotoga maritima shows a high level of heat and chemical stability. When incubated at 90 °C or in 8 M urea, the enzyme showed little or no loss of activity, unlike the Escherichia coli enzyme. The active site is very similar to that of the E. coli enzyme, and at mesophilic temperatures the two enzymes have similar kinetic constants. Like other forms of the enzyme, T. maritima DHDPS is a tetramer in solution, with a sedimentation coefficient of 7.2 S and molar mass of 133 kDa. However, the residues involved in the interface between different subunits in the tetramer differ from those of E. coli and include two cysteine residues poised to form a disulfide bond. Thus the increased heat and chemical stability of the T. maritima DHDPS enzyme is, at least in part, explained by an increased number of inter-subunit contacts. Unlike the plant or E. coli enzyme, the thermophilic DHDPS enzyme is not inhibited by (S)-lysine, suggesting that feedback control of the lysine biosynthetic pathway evolved later in the bacterial lineage.
Skip Nav Destination
Article navigation
December 2006
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkEditorial Board
Research Article|
November 14 2006
Dihydrodipicolinate synthase from Thermotoga maritima
F. Grant Pearce;
F. Grant Pearce
1
*School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand
1Correspondence may be addressed to either of the authors (email grant.pearce@canterbury.ac.nz and juliet.gerrard@canterbury.ac.nz).
Search for other works by this author on:
Matthew A. Perugini;
Matthew A. Perugini
†Bio21 Molecular Science and Biotechnology Institute, and the Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC 3010, Australia
Search for other works by this author on:
Hannah J. Mckerchar;
Hannah J. Mckerchar
*School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand
Search for other works by this author on:
Juliet A. Gerrard
Juliet A. Gerrard
1
*School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8020, New Zealand
1Correspondence may be addressed to either of the authors (email grant.pearce@canterbury.ac.nz and juliet.gerrard@canterbury.ac.nz).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
May 24 2006
Revision Received:
July 17 2006
Accepted:
July 27 2006
Accepted Manuscript online:
July 27 2006
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London
2006
Biochem J (2006) 400 (2): 359–366.
Article history
Received:
May 24 2006
Revision Received:
July 17 2006
Accepted:
July 27 2006
Accepted Manuscript online:
July 27 2006
Citation
F. Grant Pearce, Matthew A. Perugini, Hannah J. Mckerchar, Juliet A. Gerrard; Dihydrodipicolinate synthase from Thermotoga maritima. Biochem J 1 December 2006; 400 (2): 359–366. doi: https://doi.org/10.1042/BJ20060771
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.