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1w3i
From Proteopedia
| 1w3i, resolution 1.70Å () | |||||||||
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| Sites: | |||||||||
| Ligands: | , | ||||||||
| Activity: | 2-dehydro-3-deoxyglucarate aldolase, with EC number 4.1.2.20 | ||||||||
| Domains: | KDG_aldolase, DapA | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
SULFOLOBUS SOLFATARICUS 2-KETO-3-DEOXYGLUCONATE (KDG) ALDOLASE COMPLEX WITH PYRUVATE
The hyperthermophilic Archaea Sulfolobus solfataricus grows optimally above 80 degrees C and metabolizes glucose by a non-phosphorylative variant of the Entner-Doudoroff pathway. In this pathway glucose dehydrogenase and gluconate dehydratase catalyze the oxidation of glucose to gluconate and the subsequent dehydration of gluconate to D-2-keto-3-deoxygluconate (KDG). KDG aldolase (KDGA) then catalyzes the cleavage of KDG to D-glyceraldehyde and pyruvate. It has recently been shown that all the enzymes of this pathway exhibit a catalytic promiscuity that also enables them to be used for the metabolism of galactose. This phenomenon, known as metabolic pathway promiscuity, depends crucially on the ability of KDGA to cleave KDG and D-2-keto-3-deoxygalactonate (KDGal), in both cases producing pyruvate and D-glyceraldehyde. In turn, the aldolase exhibits a remarkable lack of stereoselectivity in the condensation reaction of pyruvate and D-glyceraldehyde, forming a mixture of KDG and KDGal. We now report the structure of KDGA, determined by multiwavelength anomalous diffraction phasing, and confirm that it is a member of the tetrameric N-acetylneuraminate lyase superfamily of Schiff base-forming aldolases. Furthermore, by soaking crystals of the aldolase at more than 80 degrees C below its temperature activity optimum, we have been able to trap Schiff base complexes of the natural substrates pyruvate, KDG, KDGal, and pyruvate plus D-glyceraldehyde, which have allowed rationalization of the structural basis of promiscuous substrate recognition and catalysis. It is proposed that the active site of the enzyme is rigid to keep its thermostability but incorporates extra functionality to be promiscuous.
The structural basis for substrate promiscuity in 2-keto-3-deoxygluconate aldolase from the Entner-Doudoroff pathway in Sulfolobus solfataricus., Theodossis A, Walden H, Westwick EJ, Connaris H, Lamble HJ, Hough DW, Danson MJ, Taylor GL, J Biol Chem. 2004 Oct 15;279(42):43886-92. Epub 2004 Jul 20. PMID:15265860
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Cartoon representation of YagE showing the 2-fold symmetry axes between monomers. Chains A, B, C, and D are colored cyan, lime, magenta, and yellow, respectively (2v9d). of YagE (cyan) with (1nal, yellow), (1w3i, magenta), (1xky, lime), and (2ats, blue) monomers. Although YagE possesses only 23, 24, and 27% sequence identity with EcNAL, SsKDGA, EcDHDPS, respectively, their monomeric structures are all very similar. Superposition of active site residues of YagE with (magenta, 1w3i), (blue, 2ats), and (yellow, 1nal), residues are labeled according to the corresponding PDB structures. Members of the NAL protein subfamily have very similar active sites and a single amino acid substitution can significantly change their function. For example, NAL (1nal) gets DHDPS activity by substitution of a (orange) to (blue) at position 142. The possible active site region of YagE demonstrates closest sequence similarity to the active site of KDG aldolase of SsKDGA (1w3i) and NAL of EcNAL (1nal) (yellow), suggesting that this protein can perform either of these functions. Although the active site of EcDHDPS (1xky) and BaDHDPS (2ats) shows similarities, the important residue that differentiates between NAL and DHDPS, namely Leu142 (in 1nal), is also present in YagE (labeled cyan) at that particular position suggesting that YagE performs a NAL-related function rather than DHDPS-related one.
About this Structure
1W3I is a 4 chains structure of sequences from Sulfolobus solfataricus. Full crystallographic information is available from OCA.
References
- Theodossis A, Walden H, Westwick EJ, Connaris H, Lamble HJ, Hough DW, Danson MJ, Taylor GL. The structural basis for substrate promiscuity in 2-keto-3-deoxygluconate aldolase from the Entner-Doudoroff pathway in Sulfolobus solfataricus. J Biol Chem. 2004 Oct 15;279(42):43886-92. Epub 2004 Jul 20. PMID:15265860 doi:10.1074/jbc.M407702200
- Manicka S, Peleg Y, Unger T, Albeck S, Dym O, Greenblatt HM, Bourenkov G, Lamzin V, Krishnaswamy S, Sussman JL. Crystal structure of YagE, a putative DHDPS-like protein from Escherichia coli K12. Proteins. 2008 Jun;71(4):2102-8. PMID:18361457 doi:10.1002/prot.22023
Page seeded by OCA on Tue Feb 17 11:52:03 2009
