Structural basis for the recognition of carbohydrates by human galectin-7.
Knowledge about carbohydrate recognition domains of galectins, formerly known as S-type animal lectins, is important in understanding their role(s) in cell-cell interactions. Here we report the crystal structure of human galectin-7 (hGal-7), in free form and in the presence of galactose, galactosamine, lactose, and N-acetyl-lactosamine at high resolution. This is the first structure of a galectin determined in both free and carbohydrate-bound forms. The structure shows a fold similar to that of the prototype galectins -1 and -2, but has greater similarity to a related galectin molecule, Gal-10. Even though the carbohydrate-binding residues are conserved, there are significant changes in this pocket due to shortening of a loop structure. The monomeric hGal-7 molecule exists as a dimer in the crystals, but adopts a packing arrangement considerably different from that of Gal-1 and Gal-2, which has implications for carbohydrate recognition.
Department of Biology and Biochemistry, University of Bath, UK.
D D
DD
Leonidas
E H
EH
Vatzaki
H
H
Vorum
J E
JE
Celis
P
P
Madsen
K R
KR
Acharya
D000595:Amino Acid Sequence; D000606:Amino Sugars / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D050260:Carbohydrate Metabolism; D002417:Cattle; D003460:Crystallization; D018360:Crystallography, X-Ray; D005688:Galactosamine / Q000378:metabolism; D005690:Galactose / Q000378:metabolism; D037161:Galectins; D006801:Humans; D007785:Lactose / Q000378:metabolism; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D013329:Structure-Activity Relationship
D000606:Amino Sugars; D037161:Galectins; C092525:LGALS7 protein, human; D037102:Lectins; C000458:N-acetyllactosamine; D005688:Galactosamine; D007785:Lactose; D005690:Galactose