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PDBsum entry 1bk4
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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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Structure of rabbit liver fructose 1,6-Bisphosphatase at 2.3 a resolution.
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Authors
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C.M.Weeks,
A.W.Roszak,
M.Erman,
R.Kaiser,
H.Jörnvall,
D.Ghosh.
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Ref.
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Acta Crystallogr D Biol Crystallogr, 1999,
55,
93.
[DOI no: ]
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PubMed id
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Abstract
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The three-dimensional structure of the R form of rabbit liver fructose
1,6-bisphosphatase (Fru-1,6-Pase; E.C. 3.1.3.11) has been determined by a
combination of heavy-atom and molecular-replacement methods. A model, which
includes 2394 protein atoms and 86 water molecules, has been refined at 2.3 A
resolution to a crystallographic R factor of 0.177. The root-mean-square
deviations of bond distances and angles from standard geometry are 0.012 A and
1.7 degrees, respectively. This structural result, in conjunction with recently
redetermined amino-acid sequence data, unequivocally establishes that the rabbit
liver enzyme is not an aberrant bisphosphatase as once believed, but is indeed
homologous to other Fru-1,6-Pases. The root-mean-square deviation of the Calpha
atoms in the rabbit liver structure from the homologous atoms in the pig kidney
structure complexed with the product, fructose 6-phosphate, is 0.7 A.
Fru-1,6-Pases are homotetramers, and the rabbit liver protein crystallizes in
space group I222 with one monomer in the asymmetric unit. The structure contains
a single endogenous Mg2+ ion coordinated by Glu97, Asp118, Asp121 and Glu280 at
the site designated metal site 1 in pig kidney Fru-1,6-Pase R-form complexes. In
addition, two sulfate ions, which are found at the positions normally occupied
by the 6-phosphate group of the substrate, as well as the phosphate of the
allosteric inhibitor AMP appear to provide stability. Met177, which has
hydrophobic contacts with the adenine moiety of AMP in pig kidney T-form
complexes, is replaced by glycine. Binding of a non-hydrolyzable substrate
analog, beta-methyl-fructose 1,6-bisphosphate, at the catalytic site is also
examined.
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Figure 6.
Figure 6 Coordination of the sulfate ion at the site occupied
by the 6-phosphate group of pig kidney enzyme complexes with
product, competitive inhibitor, substrate and substrate analogs.
Hydrogen-bond distances  3.2
Å are indicated.
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Figure 7.
Figure 7 Coordination of the sulfate ion at the site occupied
by the phosphate moiety of AMP in the pig kidney enzyme
complexes. Hydrogen-bond distances 3.2
Å are indicated.
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The above figures are
reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr
(1999,
55,
93-0)
copyright 1999.
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