Amino acid sequence and tertiary structure of Cratylia mollis seed lectin.
Carbohydrate-protein 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 A 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 Calpha positional differences are below 3.5 A. Cramoll and Con A have identical binding sites for MealphaMan, 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.
De Souza
Gustavo A
GA
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.
Oliveira
Paulo S L
PS
Trapani
Stefano
S
Santos
Ana Célia O
AC
Rosa
José C
JC
Laure
Helen J
HJ
Faça
Vitor M
VM
Correia
Maria T S
MT
Tavares
Gisele A
GA
Oliva
Glaucius
G
Coelho
Luana C B B
LC
Greene
Lewis J
LJ
D000595:Amino Acid Sequence; D001665:Binding Sites; D002241:Carbohydrates / Q000737:chemistry; D003208:Concanavalin A / Q000737:chemistry; D018360:Crystallography, X-Ray; D007887:Fabaceae / Q000737:chemistry*; D006860:Hydrogen Bonding; D037102:Lectins / Q000737:chemistry*; D008670:Metals / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012639:Seeds / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D002241:Carbohydrates; D037102:Lectins; D008670:Metals; D003208:Concanavalin A