Structural highlights
Function
[DAPA_ECOLI] Catalyzes the condensation of (S)-aspartate-beta-semialdehyde [(S)-ASA] and pyruvate to 4-hydroxy-tetrahydrodipicolinate (HTPA).[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Dihydrodipicolinate synthase (DHDPS) is an essential enzyme in (S)-lysine biosynthesis and an important antibiotic target. All X-ray crystal structures solved to date reveal a homotetrameric enzyme. In order to explore the role of this quaternary structure, dimeric variants of Escherichia coli DHDPS were engineered and their properties were compared to those of the wild-type tetrameric form. X-ray crystallography reveals that the active site is not disturbed when the quaternary structure is disrupted. However, the activity of the dimeric enzymes in solution is substantially reduced, and a tetrahedral adduct of a substrate analogue is observed to be trapped at the active site in the crystal form. Remarkably, heating the dimeric enzymes increases activity. We propose that the homotetrameric structure of DHDPS reduces dynamic fluctuations present in the dimeric forms and increases specificity for the first substrate, pyruvate. By restricting motion in a key catalytic motif, a competing, non-productive reaction with a substrate analogue is avoided. Small-angle X-ray scattering and mutagenesis data, together with a B-factor analysis of the crystal structures, support this hypothesis and lead to the suggestion that in at least some cases, the evolution of quaternary enzyme structures might serve to optimise the dynamic properties of the protein subunits.
Evolution of quaternary structure in a homotetrameric enzyme.,Griffin MD, Dobson RC, Pearce FG, Antonio L, Whitten AE, Liew CK, Mackay JP, Trewhella J, Jameson GB, Perugini MA, Gerrard JA J Mol Biol. 2008 Jul 18;380(4):691-703. Epub 2008 May 22. PMID:18556019[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Devenish SR, Blunt JW, Gerrard JA. NMR studies uncover alternate substrates for dihydrodipicolinate synthase and suggest that dihydrodipicolinate reductase is also a dehydratase. J Med Chem. 2010 Jun 24;53(12):4808-12. doi: 10.1021/jm100349s. PMID:20503968 doi:10.1021/jm100349s
- ↑ Blickling S, Renner C, Laber B, Pohlenz HD, Holak TA, Huber R. Reaction mechanism of Escherichia coli dihydrodipicolinate synthase investigated by X-ray crystallography and NMR spectroscopy. Biochemistry. 1997 Jan 7;36(1):24-33. PMID:8993314 doi:10.1021/bi962272d
- ↑ Griffin MD, Dobson RC, Pearce FG, Antonio L, Whitten AE, Liew CK, Mackay JP, Trewhella J, Jameson GB, Perugini MA, Gerrard JA. Evolution of quaternary structure in a homotetrameric enzyme. J Mol Biol. 2008 Jul 18;380(4):691-703. Epub 2008 May 22. PMID:18556019 doi:10.1016/j.jmb.2008.05.038
