1db3 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.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Background: GDP-mannose 4,6 dehydratase (GMD) catalyzes the conversion of GDP-(D)-mannose to GDP-4-keto, 6-deoxy-(D)-mannose. This is the first and regulatory step in the de novo biosynthesis of GDP-(L)-fucose. Fucose forms part of a number of glycoconjugates, including the ABO blood groups and the selectin ligand sialyl Lewis X. Defects in GDP-fucose metabolism have been linked to leukocyte adhesion deficiency type II (LADII). Results: The structure of the GDP-mannose 4,6 dehydratase apo enzyme has been determined and refined using data to 2.3 A resolution. GMD is a homodimeric protein with each monomer composed of two domains. The larger N-terminal domain binds the NADP(H) cofactor in a classical Rossmann fold and the C-terminal domain harbors the sugar-nucleotide binding site. We have determined the GMD dissociation constants for NADP, NADPH and GDP-mannose. Each GMD monomer binds one cofactor and one substrate molecule, suggesting that both subunits are catalytically competent. GDP-fucose acts as a competitive inhibitor, suggesting that it binds to the same site as GDP-mannose, providing a mechanism for the feedback inhibition of fucose biosynthesis. Conclusions: The X-ray structure of GMD reveals that it is a member of the short-chain dehydrogenase/reductase (SDR) family of proteins. We have modeled the binding of NADP and GDP-mannose to the enzyme and mutated four of the active-site residues to determine their function. The combined modeling and mutagenesis data suggests that at position 133 threonine substitutes serine as part of the serine-tyrosine-lysine catalytic triad common to the SDR family and Glu 135 functions as an active-site base.
Structural and kinetic analysis of Escherichia coli GDP-mannose 4,6 dehydratase provides insights into the enzyme's catalytic mechanism and regulation by GDP-fucose.,Somoza JR, Menon S, Schmidt H, Joseph-McCarthy D, Dessen A, Stahl ML, Somers WS, Sullivan FX Structure. 2000 Feb 15;8(2):123-35. PMID:10673432[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
↑Somoza JR, Menon S, Schmidt H, Joseph-McCarthy D, Dessen A, Stahl ML, Somers WS, Sullivan FX. Structural and kinetic analysis of Escherichia coli GDP-mannose 4,6 dehydratase provides insights into the enzyme's catalytic mechanism and regulation by GDP-fucose. Structure. 2000 Feb 15;8(2):123-35. PMID:10673432
