title: Three-dimensional structural aspects of protein-polysaccharide interactions.
abstract: Linear polysaccharides are typically composed of repeating mono- or disaccharide units and are ubiquitous among living organisms. Polysaccharide diversity arises from chain-length variation, branching, and additional modifications. Structural diversity is associated with various physiological functions, which are often regulated by cognate polysaccharide-binding proteins. Proteins that interact with linear polysaccharides have been identified or developed, such as galectins and polysaccharide-specific antibodies, respectively. Currently, data is accumulating on the three-dimensional structure of polysaccharide-binding proteins. These proteins are classified into two types: exo-type and endo-type. The former group specifically interacts with the terminal units of polysaccharides, whereas the latter with internal units. In this review, we describe the structural aspects of exo-type and endo-type protein-polysaccharide interactions. Further, we discuss the structural basis for affinity and specificity enhancement in the face of inherently weak binding interactions.
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. mnagae@riken.jp.
authors.forename: Masamichi
authors.initials: M
authors.lastname: Nagae
authors.affiliation: Structural Glycobiology Team, Systems Glycobiology Research Group, RIKEN-Max Planck Joint Research Center, RIKEN Global Research Cluster, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan. yyoshiki@riken.jp.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Yamaguchi
mesh_terms: D021621:Imaging, Three-Dimensional / Q000379:methods*; D008958:Models, Molecular; D008968:Molecular Conformation; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry* / Q000145:classification / Q000378:metabolism
chemical_list: D011134:Polysaccharides; D011506:Proteins