Specificity of the binding site of the sialic acid-binding lectin from ovine placenta, deduced from interactions with synthetic analogues.
The specificity of the sialic acid-binding lectin from ovine placenta was examined in detail by haemagglutination inhibition assays applying a panel of 32 synthetic sialic acid analogues. The carboxylic acid group is a prerequisite for the interaction with the lectin, the alpha-anomer of the methyl glycoside is only a little more effective as an inhibitor than the beta-anomer and the most potent inhibitor was 9-deoxy-10-carboxylic acid Neu5Ac, followed by 4-oxo-Neu5Ac. In contrast to the majority of known sialic acid-binding lectins, the N-acetyl group of Neu5Ac is not indispensable for binding, neither is the hydroxyl group at C-9 since substitutions at this carbon atom are well tolerated. Furthermore, all sulfur-containing substituents at C-9 enhanced the affinity of the lectin. This is the first sialic acid-binding lectin found to strongly bind thio derivatives.
Troncoso
M F
MF
Instituto de Química y Fisicoquímica Biológicas (IQUIFIB) (UBA-CONICET), Facultad de Farmacia y Bioquímica, Junín, Buenos Aires, Argentina.
Iglesias
M M
MM
Isecke
R
R
Todel
C W
CW
Brossmer
R
R
D000818:Animals; D001665:Binding Sites; D005260:Female; D005990:Glycerol / Q000737:chemistry; D006385:Hemagglutination Inhibition Tests; D037102:Lectins / Q000737:chemistry / Q000378:metabolism*; D019158:N-Acetylneuraminic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D009438:Neuraminic Acids / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D010920:Placenta / Q000737:chemistry*; D011247:Pregnancy; D011817:Rabbits; D012756:Sheep; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
C432128:5-acetyl-9-deoxy-10-carboxyneuraminic acid; D037102:Lectins; C055828:N-acetyl-4-oxoneuraminic acid; D009438:Neuraminic Acids; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; D019158:N-Acetylneuraminic Acid; D005990:Glycerol