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1nal
From Proteopedia
| 1nal, resolution 2.20Å () | |||||||||
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| Ligands: | |||||||||
| Activity: | N-acetylneuraminate lyase, with EC number 4.1.3.3 | ||||||||
| Domains: | NAL, DapA | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
THE THREE-DIMENSIONAL STRUCTURE OF N-ACETYLNEURAMINATE LYASE FROM ESCHERICHIA COLI
BACKGROUND: N-acetylneuraminate lyase catalyzes the cleavage of N-acetylneuraminic acid (sialic acid) to form pyruvate and N-acetyl-D-mannosamine. The enzyme plays an important role in the regulation of sialic acid metabolism in bacteria. The reverse reaction can be exploited for the synthesis of sialic acid and some of its derivatives. RESULTS: The structure of the enzyme from Escherichia coli has been determined to 2.2 A resolution by X-ray crystallography. The enzyme is shown to be a tetramer, in which each subunit consists of an alpha/beta-barrel domain followed by a carboxy-terminal extension of three alpha-helices. CONCLUSIONS: The active site of the enzyme is tentatively identified as a pocket at the carboxy-terminal end of the eight-stranded beta-barrel. Lys165 lies within this pocket and is probably the reactive residue which forms a Schiff base intermediate with the substrate. The sequence of N-acetylneuraminate lyase has similarities to those of dihydrodipicolinate synthase and MosA (an enzyme implicated in rhizopine synthesis) suggesting that these last two enzymes share a similar structure to N-acetylneuraminate lyase.
The three-dimensional structure of N-acetylneuraminate lyase from Escherichia coli., Izard T, Lawrence MC, Malby RL, Lilley GG, Colman PM, Structure. 1994 May 15;2(5):361-9. PMID:8081752
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
1NAL is a 4 chains structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
References
- Izard T, Lawrence MC, Malby RL, Lilley GG, Colman PM. The three-dimensional structure of N-acetylneuraminate lyase from Escherichia coli. Structure. 1994 May 15;2(5):361-9. PMID:8081752
- 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 01:48:31 2009
