| Structural highlights
1e7q is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , , |
| Related: | 1bws, 1bsv, 1fxs, 1gfs, 1e6u, 1e7r, 1e7s |
| Resources: | FirstGlance, OCA, RCSB, PDBsum |
Function
[FCL_ECOLI] Catalyzes the two-step NADP-dependent conversion of GDP-4-dehydro-6-deoxy-D-mannose to GDP-fucose, involving an epimerase and a reductase reaction.[1] [2] [3]
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
GDP-4-keto-6-deoxy-d-mannose epimerase/reductase is a bifunctional enzyme responsible for the last step in the biosynthesis of GDP-l-fucose, the substrate of fucosyl transferases. Several cell-surface antigens, including the leukocyte Lewis system and cell-surface antigens in pathogenic bacteria, depend on the availability of GDP-l-fucose for their expression. Therefore, the enzyme is a potential target for therapy in pathological states depending on selectin-mediated cell-to-cell interactions. Previous crystallographic investigations have shown that GDP-4-keto-6-deoxy-d-mannose epimerase/reductase belongs to the short-chain dehydrogenase/reductase protein homology family. The enzyme active-site region is at the interface of an N-terminal NADPH-binding domain and a C-terminal domain, held to bind the substrate. The design, expression and functional characterization of seven site-specific mutant forms of GDP-4-keto-6-deoxy-d-mannose epimerase/reductase are reported here. In parallel, the crystal structures of the native holoenzyme and of three mutants (Ser107Ala, Tyr136Glu and Lys140Arg) have been investigated and refined at 1. 45-1.60 A resolution, based on synchrotron data (R-factors range between 12.6 % and 13.9 %). The refined protein models show that besides the active-site residues Ser107, Tyr136 and Lys140, whose mutations impair the overall enzymatic activity and may affect the coenzyme binding mode, side-chains capable of proton exchange, located around the expected substrate (GDP-4-keto-6-deoxy-d-mannose) binding pocket, are selectively required during the epimerization and reduction steps. Among these, Cys109 and His179 may play a primary role in proton exchange between the enzyme and the epimerization catalytic intermediates. Finally, the additional role of mutated active-site residues involved in substrate recognition and in enzyme stability has been analyzed.
Probing the catalytic mechanism of GDP-4-keto-6-deoxy-d-mannose Epimerase/Reductase by kinetic and crystallographic characterization of site-specific mutants.,Rosano C, Bisso A, Izzo G, Tonetti M, Sturla L, De Flora A, Bolognesi M J Mol Biol. 2000 Oct 13;303(1):77-91. PMID:11021971[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Andrianopoulos K, Wang L, Reeves PR. Identification of the fucose synthetase gene in the colanic acid gene cluster of Escherichia coli K-12. J Bacteriol. 1998 Feb;180(4):998-1001. PMID:9473059
- ↑ Menon S, Stahl M, Kumar R, Xu GY, Sullivan F. Stereochemical course and steady state mechanism of the reaction catalyzed by the GDP-fucose synthetase from Escherichia coli. J Biol Chem. 1999 Sep 17;274(38):26743-50. PMID:10480878
- ↑ Rosano C, Bisso A, Izzo G, Tonetti M, Sturla L, De Flora A, Bolognesi M. Probing the catalytic mechanism of GDP-4-keto-6-deoxy-d-mannose Epimerase/Reductase by kinetic and crystallographic characterization of site-specific mutants. J Mol Biol. 2000 Oct 13;303(1):77-91. PMID:11021971 doi:10.1006/jmbi.2000.4106
- ↑ Rosano C, Bisso A, Izzo G, Tonetti M, Sturla L, De Flora A, Bolognesi M. Probing the catalytic mechanism of GDP-4-keto-6-deoxy-d-mannose Epimerase/Reductase by kinetic and crystallographic characterization of site-specific mutants. J Mol Biol. 2000 Oct 13;303(1):77-91. PMID:11021971 doi:10.1006/jmbi.2000.4106
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