Structural features of lectins and their binding sites

Complex glycans displayed on proteins or on cell surfaces are information carriers. They determine the location and fate of glycoproteins or act as recognition sites for signaling molecules and pathogens. Lectins are carbohydrate binding proteins capable of reading this glycocode. A wide variety of unrelated lectin families exist that carryout many different biological functions. X-ray crystallography has revealed a wide variety of lectin folds and carbohydrate binding site architectures but also some striking cases of convergent evolution at the level of the carbohydrate binding site, the protein fold and even subunit association. These similarities likely arose from similar functional needs.