6v7j
The C2221 crystal form of canavalin at 173 K
Structural highlights
FunctionCANA_CANEN Seed storage protein. Publication Abstract from PubMedX-ray intensities extending to 1.4 A resolution were collected on the P63 hexagonal crystal form of canavalin, and extended to 1.9 A for the orthorhombic C2221 crystals. Structure determination of a new crystal form of canavalin having space group P212121 is reported as well. Both the N and C terminal cupin domains contained identifiable ligands. For hexagonal crystals, in the cavity of the C terminal cupin, a molecule of benzoic acid was found, bound through carboxyl oxygens to Histidine 297, asparagine 284 and Arginine 376. The benzene ring was immersed in a cluster of at least 8 hydrophobic amino acid side chains. The N terminal cupin contained a molecule of citrate. Benzoic acid was also found to be present in the C terminal cupins of in the C2221 and P212121 crystal forms. In rhombohedral crystals, the C terminal cupin domain appeared to be occupied by a phosphate ion, but this was ambiguous. In cubic crystals, both domains were vacant. The N terminal cupin domains of canavalin in the P212121 and rhombohedral crystals were also vacant, but the N terminal cupin domain of the C2221 crystals contained a ligand whose identity is uncertain, but which has been modeled as HEPES buffer. A possible physiological role for the ligands and their complexes with canavalin is considered. Binding of benzoic acid and anions within the cupin domains of the vicilin protein canavalin from jack bean (Canavalia ensiformis): Crystal structures.,McPherson A Biochem Biophys Res Commun. 2020 Jan 23. pii: S0006-291X(20)30176-5. doi:, 10.1016/j.bbrc.2020.01.101. PMID:31983433[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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