Lectin-carbohydrate complexes of plants and animals: an atomic view.

Lectins are a structurally diverse class of proteins, their only common features being the ability to bind carbohydrates specifically and reversibly, and to agglutinate cells. Some, however, can be grouped together into distinct families, such as those of the legumes or the cereals that are structurally similar, or the C-type (Ca(2+)-dependent) animal lectins that contain homologous carbohydrate recognition domains. Recent high-resolution X-ray crystallographic studies have revealed the structures of the sugar complexes of over half a dozen lectins. These studies demonstrate that the combining sites of lectins are also structurally diverse, although they may be similar in the same family.