Complex carbohydrate-lectin interaction at the interface: a model for cellular adhesion. I. Effect of vesicle size on the kinetics of aggregation between a fatty acid conjugate of lectin and a liposomal asialoganglioside.
Two types of phospholipid vesicles capable of mutual recognition have been tailor-made to serve as a model system for the study of carbohydrate-mediated cellular adhesion. One of the vesicles contained a fatty acid conjugate of a galactose specific lectin (lectin vesicle) and the other an asialoganglioside with a reactive terminal galactose residue (galactose vesicle). The kinetics of aggregation of these two types of vesicles was followed by monitoring time-dependent change in turbidity. A 10-100-fold enhancement in the forward rate constant (kf ranging from 7.1 x 10(5) to 4.5 x 10(7) M-1.s-1 at 27 degrees C) was observed when compared with that for the lectin-galactose system in solution (kf being 4.5 x 10(5) M-1.s-1), reported in the literature. A study of the influence of vesicle size on the rate of aggregation showed that enhancement depended on the curvature of the galactose vesicle rather than the density of asialoganglioside suggesting a possible diffusion in the plane of the membrane. The ratio, kf/kd is found to be approx. 10(10) M-1 indicating that the formation of multiple bonds plays a role for stable adhesion.
Chakrabarti
A
A
Department of Biochemistry, Indian Institute of Science, Bangalore.
Podder
S K
SK
D002448:Cell Adhesion; D002462:Cell Membrane / Q000502:physiology; D005690:Galactose; D006028:Glycosphingolipids; D007700:Kinetics; D037102:Lectins; D008081:Liposomes; D008823:Micelles; D008854:Microscopy, Electron; D008954:Models, Biological; D037121:Plant Lectins
D006028:Glycosphingolipids; D037102:Lectins; D008081:Liposomes; D008823:Micelles; D037121:Plant Lectins; C017707:Ricinus communis agglutinin-1; D005690:Galactose