Crystal structure of the Marasmius oreades mushroom lectin in complex with a xenotransplantation epitope.
MOA, a lectin from the mushroom Marasmius oreades, is one of the few reagents that specifically agglutinate blood group B erythrocytes. Further, it is the only lectin known to have exclusive specificity for Galalpha(1,3)Gal-containing sugar epitopes, which are antigens that pose a severe barrier to animal-to-human organ transplantation. We describe here the structure of MOA at 2.4 A resolution, in complex with the linear trisaccharide Galalpha(1,3)Galbeta(1,4)GlcNAc. The structure is dimeric, with two distinct domains per protomer: the N-terminal lectin module adopts a ricinB/beta-trefoil fold and contains three putative carbohydrate-binding sites, while the C-terminal domain serves as a dimerization interface. This latter domain, which has an unknown function, reveals a novel fold with intriguing conservation of an active site cleft. A number of indications suggest that MOA may have an enzymatic function in addition to the sugar-binding properties.
Grahn
Elin
E
Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, NO-0315 Oslo, Norway. elin.grahn@kjemi.uio.no <elin.grahn@kjemi.uio.no>
Askarieh
Glareh
G
Holmner
Asa
A
Tateno
Hiroaki
H
Winter
Harry C
HC
Goldstein
Irwin J
IJ
Krengel
Ute
U
D000363:Agaricales / Q000378:metabolism*; D000595:Amino Acid Sequence; D002241:Carbohydrates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D019281:Dimerization; D000939:Epitopes / Q000737:chemistry*; D037102:Lectins / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000737:chemistry*; D012276:Ricin / Q000737:chemistry; D014183:Transplantation, Heterologous
D002241:Carbohydrates; D000939:Epitopes; D037102:Lectins; D011506:Proteins; D012276:Ricin