Structural and functional characterization of the GalNAc/Gal-specific lectin from the phytopathogenic ascomycete Sclerotinia sclerotiorum (Lib.) de Bary.
The lectin found in mycelium and sclerotes of the phytopathogenic fungus Sclerotinia sclerotiorum is a homodimer consisting of two identical non-covalently bound subunits of 16,000 Da. CD spectra analysis revealed that the S. sclerotiorum agglutinin (SSA) contains predominantly beta-sheet structures. SSA exhibits specificity towards GalNAc whereby the hydroxyls at positions 4 and 6 of the pyranose ring play a key role in the interaction with simple sugars. The carbohydrate-binding site of SSA can also accommodate disaccharides. The N-terminal sequence of SSA shares no significant similarity with any other protein except a lectin from the Sclerotiniaceae species Ciborinia camelliae. A comparison of SSA and the lectins from C. camelliae and some previously characterized lectins indicates that the Sclerotiniaceae lectins form a homogeneous family of fungal lectins. This newly identified lectin family, which is structurally unrelated to any other family of fungal lectins, is most probably confined to the Ascomycota.
Candy
Laure
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Signaux et Messages Cellulaires chez les Végétaux, UMR CNRS-UPS 5546, Pôle de Biotechnologie végétale, BP 17, 24 Chemin de Borde Rouge, Castanet-Tolosan 31326, France.
Van Damme
Els J M
EJ
Peumans
Willy J
WJ
Menu-Bouaouiche
Laurence
L
Erard
Monique
M
Rougé
Pierre
P
D000116:Acetylgalactosamine / Q000378:metabolism; D000373:Agglutinins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001203:Ascomycota / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D001665:Binding Sites; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005690:Galactose / Q000378:metabolism; D037102:Lectins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid
D000373:Agglutinins; D005656:Fungal Proteins; D037102:Lectins; D000116:Acetylgalactosamine; D005690:Galactose