Structural analysis of the recognition mechanism of poly-N-acetyllactosamine by the human galectin-9 N-terminal carbohydrate recognition domain.
Galectins are a family of beta-galactoside-specific lectins bearing a conserved carbohydrate recognition domain. Interactions between galectins and poly-N-acetyllactosamine sequences are critical in a variety of biological processes. Galectin-9, a member of the galectin family, has two carbohydrate recognition domains at both the N- and C-terminal regions. Here we report the crystal structure of the human galectin-9 N-terminal carbohydrate recognition domain in complex with N-acetyllactosamine dimers and trimers. These complex structures revealed that the galectin-9 N-terminal carbohydrate recognition domain can recognize internal N-acetyllactosamine units within poly-N-acetyllactosamine chains. Based on these complex structures, we propose two putative recognition modes for poly-N-acetyllactosamine binding by galectins.
Nagae
Masamichi
M
Structural Biology Research Center, Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan.
Nishi
Nozomu
N
Murata
Takeomi
T
Usui
Taichi
T
Nakamura
Takanori
T
Wakatsuki
Soichi
S
Kato
Ryuichi
R
D001665:Binding Sites; D018360:Crystallography, X-Ray; D037161:Galectins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
D037161:Galectins; C105032:LGALS9 protein, human; D011134:Polysaccharides; C037199:poly-N-acetyllactosamine