Wheat germ agglutinin isolectin 3 (WGA3) was crystallized from 10 mM acetate buffer at pH 4.9 containing 6 mM CaCl(2) and 4%(v/v) ethanol. The crystal belongs to monoclinic space group P2(1) with unit-cell dimensions a = 44.86, b = 91.02, c = 44.86 A, and beta = 110.22 degrees. The asymmetric unit contains two molecules (V(m) = 2.51 A(3) Da(-1)). The crystal structure was solved by the molecular-replacement method and was refined by the simulated-annealing method. The conventional R value was 0.191 for 19713 reflections [|F(o)| > 3sigma(F)] in the resolution range 8-1.9 A. The r.m.s. deviations from the ideal bond distances and angles were 0.014 A, and 3.0 degrees, respectively, and the estimated coordinate error was 0.2-0.25 A. The two molecules in the asymmetric unit are related by the pseudo twofold symmetry and form a dimer structure. The backbone structures of the two subunits are nearly identical with the r.m.s. difference of 0.36 A for the superposition of equivalent C(alpha) atoms. The dimer structure is very similar to those of isolectins 1 and 2 with the r.m.s. difference of 0.35-0.39 A for the C(alpha) superposition. Since amino-acid residues which differ from those of isolectin 1 or 2 are not involved in the contact between the two subunits, the subunit-subunit interaction is not significantly affected by the replacement of these residues. As a result, the geometry of the sugar-binding sites which are located at the interface between the two subunit molecules is basically conserved among three isolectins.
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Wheat germ agglutinin isolectin 3 (WGA3) was crystallized from 10 mM acetate buffer at pH 4.9 containing 6 mM CaCl(2) and 4%(v/v) ethanol. The crystal belongs to monoclinic space group P2(1) with unit-cell dimensions a = 44.86, b = 91.02, c = 44.86 A, and beta = 110.22 degrees. The asymmetric unit contains two molecules (V(m) = 2.51 A(3) Da(-1)). The crystal structure was solved by the molecular-replacement method and was refined by the simulated-annealing method. The conventional R value was 0.191 for 19713 reflections [|F(o)| > 3sigma(F)] in the resolution range 8-1.9 A. The r.m.s. deviations from the ideal bond distances and angles were 0.014 A, and 3.0 degrees, respectively, and the estimated coordinate error was 0.2-0.25 A. The two molecules in the asymmetric unit are related by the pseudo twofold symmetry and form a dimer structure. The backbone structures of the two subunits are nearly identical with the r.m.s. difference of 0.36 A for the superposition of equivalent C(alpha) atoms. The dimer structure is very similar to those of isolectins 1 and 2 with the r.m.s. difference of 0.35-0.39 A for the C(alpha) superposition. Since amino-acid residues which differ from those of isolectin 1 or 2 are not involved in the contact between the two subunits, the subunit-subunit interaction is not significantly affected by the replacement of these residues. As a result, the geometry of the sugar-binding sites which are located at the interface between the two subunit molecules is basically conserved among three isolectins.
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skos:exactMatch | |
uniprot:name |
Acta Crystallogr. D
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uniprot:author |
Harata K.,
Jigami Y.,
Nagahora H.
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uniprot:date |
1995
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uniprot:pages |
1013-1019
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uniprot:title |
X-ray structure of wheat germ agglutinin isolectin 3.
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uniprot:volume |
51
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dc-term:identifier |
doi:10.1107/S0907444995004070
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