Carbohydrate-protein interactions at interfaces: synthesis of thiolactosyl glycolipids and design of a working model for surface plasmon resonance.
Thiolactosyl lipids designed for carbohydrate-protein binding studies have been synthesised. One representative was selected for binding studies with a plant lectin RCA120, the agglutinin from Ricinus communis. The interactions were measured quantitatively in real time using a BIAcore surface plasmon resonance instrument. Removal of much of the galactose from the thiolactosyl lipid in situ with beta-galactosidase showed that the lectin binding was highly specific. A dissociation constant KD = 8.77 x 10(-8) M was measured for 1-[2-[2-(2-[beta-D-galactopyranosyl-(1-->4)-1-thio-beta-D -glucopyranosyl]ethoxy)ethoxy]ethoxy]octadecane 30 which is four orders of magnitude greater than that determined for binding to lactose in solution. A concentration of lactose of > 80 mM was required to block the lectin binding to thiolactosyl lipid in a neomembrane.
Critchley
Peter
P
Department of Chemistry, University of Warwick, Coventry, UK CV4 7AL.
Willand
M Nicolas
MN
Rullay
Atvinder K
AK
Crout
David H
DH
D001665:Binding Sites; D050260:Carbohydrate Metabolism; D005690:Galactose / Q000737:chemistry; D006017:Glycolipids / Q000138:chemical synthesis* / Q000378:metabolism; D007700:Kinetics; D007785:Lactose / Q000494:pharmacology; D008956:Models, Chemical; D037121:Plant Lectins / Q000737:chemistry / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D020349:Surface Plasmon Resonance / Q000379:methods*; D001616:beta-Galactosidase / Q000737:chemistry / Q000378:metabolism
D006017:Glycolipids; D037121:Plant Lectins; D011506:Proteins; C017707:Ricinus communis agglutinin-1; D001616:beta-Galactosidase; D007785:Lactose; D005690:Galactose