Download MendeleyCrystal structure of cardosin A, a glycosylated and Arg-Gly-Asp-containing aspartic proteinase from the flowers of Cynara cardunculus L.
Frazao, C., Bento, I., Costa, J., Soares, C.M., Verissimo, P., Faro, C., Pires, E., Cooper, J., Carrondo, M.A.(1999) J Biological Chem 274: 27694-27701
- PubMed: 10488111 Search on PubMed
- DOI: https://doi.org/10.1074/jbc.274.39.27694
- Primary Citation Related Structures:
1B5F - PubMed Abstract:
Aspartic proteinases (AP) have been widely studied within the living world, but so far no plant AP have been structurally characterized. The refined cardosin A crystallographic structure includes two molecules, built up by two glycosylated peptide chains (31 and 15 kDa each). The fold of cardosin A is typical within the AP family. The glycosyl content is described by 19 sugar rings attached to Asn-67 and Asn-257. They are localized on the molecular surface away from the conserved active site and show a new glycan of the plant complex type. A hydrogen bond between Gln-126 and Manbeta4 renders the monosaccharide oxygen O-2 sterically inaccessible to accept a xylosyl residue, therefore explaining the new type of the identified plant glycan. The Arg-Gly-Asp sequence, which has been shown to be involved in recognition of a putative cardosin A receptor, was found in a loop between two beta-strands on the molecular surface opposite the active site cleft. Based on the crystal structure, a possible mechanism whereby cardosin A might be orientated at the cell surface of the style to interact with its putative receptor from pollen is proposed. The biological implications of these findings are also discussed.
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Apartado 127, 2780-Oeiras, Portugal.
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