1gic
CONCANAVALIN A COMPLEXED WITH METHYL ALPHA-D-GLUCOPYRANOSIDE
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OverviewOverview
The solution of the cubic crystal form (a = 167.8 A) of concanavalin A, complexed with the monosaccharide methyl alpha-D-glucopyranoside is, described. The space group has been determined as I2(1)3 rather than I23., The use of cadmium to replace cobalt at the transition metal-ion binding, site and to replace calcium at its binding site proved to be crucial to, the successful solution of the crystal structure. The relatively small, isomorphous signals of 21 e(-) for the replacement of cobalt and 28 e(-), for the replacement of calcium, yielded interpretable difference Patterson, maps. The electron-density map calculated in space group I2(1)3 at 5.4 A, resolution, based on phases derived from single- and double-substituted, cadmium differences, revealed a classical concanavalin A tetramer of 222, point symmetry, as seen in all the known crystal structures of, concanavalin A. Rigid-body refinement at 3.6 A using the refined, coordinates of saccharide-free concanavalin A converged to an R factor of, 27.4%. A molecular-replacement analysis, consistent with this crystal, structure, and initial experiences in the incorrect space group I23 are, described as these also prove to be instructive.
About this StructureAbout this Structure
1GIC is a Single protein structure of sequence from Canavalia ensiformis with GYP, MN and CA as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Structure solution of a cubic crystal of concanavalin A complexed with methyl alpha-D-glucopyranoside., Harrop SJ, Helliwell JR, Wan TC, Kalb AJ, Tong L, Yariv J, Acta Crystallogr D Biol Crystallogr. 1996 Jan 1;52(Pt 1):143-55. PMID:15299735
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