Structure-function inferences based on molecular modeling, sequence-based methods and biological data analysis of snake venom lectins.
Lectins are a structurally and functionally diverse group of proteins from different sources, capable to recognize and bind specifically carbohydrates. Several snake venoms contain calcium-dependent true lectins (SVLs) that recognize galactose. Herein, in order to enlighten some of the structure-function relationships of snake venom lectins (SVLs), we constructed theoretical models for 10 SVLs based on the Crotalus atrox lectin (CaL), the only SVL crystal structure available, and compared with other animal and plant lectins, and C-type lectin-like proteins (CLPs) that do not bind carbohydrates. Although these are theoretical structures, we could identify some SVL features, including: (i) a singular intrachain disulfide bond (Cys(38)-Cys(133)) that is not present in CLPs; (ii) a significant reorientation (39-41A) of the 80's loop position that folds back to the globular domain, assists the carbohydrate recognition domain (CRD), and orients the dimer formation, even in BfL-1 and BfL-2, which did not present the Cys(86) interchain; (iii) a CRD presenting a negative and concave surface that allows the interaction with the specific saccharide hydroxyl groups and calcium ion; (iv) the role of water molecules in some interchain interactions, similar to other animal and plant lectins; and (v) the inability of forming oligomers in contrast to CaL and some CLPs, such as convulxin.
Abreu
Paula Alvarez
PA
Laboratório de Bioquímica e Modelagem Molecular, Departamento de Biologia Celular e Molecular, Instituto de Biologia, CEG, Universidade Federal Fluminense, CEP 24001-970, Niterói, RJ, Brazil.
Albuquerque
Magaly Girão
MG
Rodrigues
Carlos Rangel
CR
Castro
Helena Carla
HC
D000595:Amino Acid Sequence; D000818:Animals; D018360:Crystallography, X-Ray; D017815:Elapidae / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D037102:Lectins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008358:Mannose / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D012910:Snake Venoms / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship; D017819:Viperidae / Q000378:metabolism
D037102:Lectins; D012910:Snake Venoms; D008358:Mannose; D005690:Galactose