Crystal structure of the C-terminal conserved domain of human GRP, a galectin-related protein, reveals a function mode different from those of galectins.

摘要

Lectins are a group of proteins that recognize carbohydrates covalently linked to proteins and lipids on the cell surface and within the extracellular matrix and have diverse physiological functions including growth regulation, cell adhesion, pre-mRNA splicing, cell migration, cell apoptosis, immune responses, and pathogen recognition. The galectins are a family of animal lectins defined by their shared conserved carbohydrate recognition domain (CRD) of about 130 amino acids and affinity for fi-galactoside sug-ars.The galectins can be classified into three subfamilies as proto-, chimera-, and tandem-repeat types based on their domain organization. Gal-1, 2, 5, 7, 10, 11, 13, 14, and 15 are prototype galectins which contain one carbohydrate-recognition domain per subunit and are usually homodimers of noncovalently linked sub-units.3'21 Gal3 is the only member of the chimera-type galectin which contains a C-terminal CRD and an N-ter-minal slightly long peptide rich in praline and glycine. Gal4, 6, 8, 9,and 12 are examples of tandem-repeat galectins which contain two CRDs joined by a linked peptide and are monomeric.