Multivalent ligand binding by serum mannose-binding protein.
The serum-type mannose-binding protein (MBP) is a defense molecule that has carbohydrate-dependent bactericidal effects. It shares with mammalian and chicken hepatic lectins similarity in the primary structure of the carbohydrate-recognition domain, as well as the ligand-binding mode: a high affinity (KD approximately nM) is generated by clustering of approximately 30 terminal target sugar residues on a macromolecule, such as bovine serum albumin, although the individual monosaccharides have low affinity (KD 0.1-1 mM). On the other hand, MBP does not manifest any significant affinity enhancement toward small, di- and trivalent ligands, in contrast to the hepatic lectins whose affinity toward divalent ligands of comparable structures increased from 100- to 1000-fold. Such differences may be explained on the basis of different subunit organization between the hepatic lectins and MBP.
D000209:Acute-Phase Proteins / Q000378:metabolism; D000818:Animals; D002240:Carbohydrate Sequence; D002352:Carrier Proteins / Q000097:blood*; D002462:Cell Membrane / Q000378:metabolism; D006020:Glycopeptides / Q000138:chemical synthesis / Q000494:pharmacology; D006023:Glycoproteins / Q000378:metabolism; D006027:Glycosides / Q000494:pharmacology; D007700:Kinetics; D008024:Ligands; D008358:Mannose / Q000378:metabolism*; D037241:Mannose-Binding Lectins; D008969:Molecular Sequence Data; D009005:Monosaccharides / Q000494:pharmacology; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000378:metabolism
D000209:Acute-Phase Proteins; D002352:Carrier Proteins; D006020:Glycopeptides; D006023:Glycoproteins; D006027:Glycosides; D008024:Ligands; D037241:Mannose-Binding Lectins; D009005:Monosaccharides; D008358:Mannose