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PDBsum entry 1fbg
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Hydrolase(phosphoric monoester)
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PDB id
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1fbg
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Crystallographic studies of the catalytic mechanism of the neutral form of fructose-1,6-Bisphosphatase.
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Authors
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Y.Zhang,
J.Y.Liang,
S.Huang,
H.Ke,
W.N.Lipscomb.
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Ref.
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Biochemistry, 1993,
32,
1844-1857.
[DOI no: ]
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PubMed id
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Abstract
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The crystal structures of fructose-1,6-bisphosphatase (EC 3.1.3.11) complexed
with substrate alone or with substrate analogues in the presence of divalent
metal ions have been determined. The substrate analogues,
2,5-anhydro-D-glucitol-1,6-bisphosphate (AhG-1,6-P2) and
2,5-anhydro-D-mannitol-1,6-bisphosphate (AhM-1,6-P2), differ from the alpha and
beta anomers of fructose-1,6-bisphosphate (Fru-1,6-P2), respectively, in that
the OH on C2 is replaced by a hydrogen atom. Structures have been refined at
resolutions of 2.5 to 3.0 A to R factors of 0.172 to 0.195 with root-mean-square
deviations of 0.012-0.018 A and 2.7-3.8 degrees from the ideal geometries of
bond lengths and bond angles, respectively. In addition, the complex of
substrate with the enzyme has been determined in the absence of metal. The
electron density at 2.5-A resolution does not distinguish between alpha and beta
anomers, which differ for the most part only in the position of the 1-phosphate
group and the orientation of the C2-hydroxyl group. The positions of the
6-phosphate and the sugar ring of the substrate analogues are almost identical
to those of the respective anomer of the substrate. In the presence of metal
ions the positions of the 1-phosphate groups of both alpha and beta analogues
differ significantly (0.8-1.0 A) from those of anomers of the substrate in the
metal-free complex. Two metal ions (Mn2+ or Zn2+) are located at the enzyme
active site of complexes of the alpha analogue AhG-1,6-P2. Metal site 1 is
coordinated by the carboxylate groups of Glu-97, Asp-118, and Glu-280 and the
1-phosphate group of substrate analogue, while the metal site 2 is coordinated
by the carboxylate groups of Glu-97, Asp-118, the 1-phosphate group of substrate
analogue, and the carbonyl oxygen of Leu-120. Both metal sites have a distorted
tetrahedral geometry. However, only one metal ion (Mg2+ or Mn2+) is found very
near the metal site 1 in the enzyme's active site in complexes of the beta
analogue AhM-1,6-P2 or for Mg2+ in the complex of the alpha analogue AhG-1,6-P2.
This single metal ion is coordinated by the carboxylate groups of Glu-97,
Asp-118, Asp-121, and Glu-280 and the 1-phosphate group of substrate analogue in
a distorted square pyramidal geometry.(ABSTRACT TRUNCATED AT 400 WORDS)
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Secondary reference #1
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Title
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Crystal structure of the neutral form of fructose-1,6-Bisphosphatase complexed with the product fructose 6-Phosphate at 2.1-A resolution.
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Authors
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H.M.Ke,
Y.P.Zhang,
J.Y.Liang,
W.N.Lipscomb.
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Ref.
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Proc Natl Acad Sci U S A, 1991,
88,
2989-2993.
[DOI no: ]
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PubMed id
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