Glycobiology Advance Access originally published online on September 9, 2003
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Glycobiology, 2003, Vol. 13, No. 12 961-972
© 2003 Oxford University Press
Amino acid sequence and tertiary structure of Cratylia mollis seed lectin
2 Centro de Quimica de Proteínas and Depto de Biologia Celular, Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14049-900 Ribeirão Preto, SP, Brazil; 3 Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970, São Carlos, SP, Brazil; 4 Instituto de Química de São Carlos, Universidade de São Paulo, 13560-970, São Carlos, SP, Brazil; 5 Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Pernambuco, Recife, PE, Brazil, and 6 Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Recif, PE, Brazil
Received on August 6, 2003; revised on August 25, 2003; accepted on August 26, 2003
Carbohydrateprotein interactions play a key role in many biological processes. Cramoll is a lectin purified from Cratylia mollis seeds that is taxonomically related to concanavalin A (Con A). Although Cramoll and Con A have the same monosaccharide specificity, they have different glycoprotein binding profiles. We report the primary structure of Cramoll, determined by Edman degradation and mass spectrometry and its 1.77 Å crystallographic structure and compare it with the three-dimensional structure of Con A in an attempt to understand how differential binding can be achieved by similar or nearly identical structures. We report here that Cramoll consists of 236 residues, with 82% identity with Con A, and that its topological architecture is essentially identical to Con A, because the C
positional differences are below 3.5 Å. Cramoll and Con A have identical binding sites for Me
Man, Mn2+, and Ca2+. However, we observed six substitutions in a groove adjacent to the extended binding site and two in the extended binding site that may explain the differences in binding of oligosaccharides and glycoproteins between Cramoll and Con A.
1 To whom correspondence should be addressed; e-mail: ljgreene{at}fmrp.usp.br