Influence of spacer length on the agglutination of glycolipid-incorporated liposomes by ConA as model membrane.
Through a systematic investigation of the agglutination of long chain mannolipid and glucolipid incorporated liposomes by concanavalin A (ConA) it was found that the agglutination was dependent on different factors. The studied factors reported here are (1) spacer length and (2) ground lipid matrix. The threshold and the relative saturating ConA binding concentration (saturation point to attain the binding saturation condition) of glycosides with varying spacer length for agglutination are dependent on the spacer length of the glycolipid. These concentrations decrease with the increasing number of in-built ethyleneoxy spacer length in the glycolipid and find its minimum with 6 spacer units; it increases then more and more with increasing number of spacer units (>6 units). This is supposed to be due to the requirement of a proper distance of the hydrophilic determinant from the liposome surface for the response by ConA (response invoking distance), which may be most favorable in case of 6 spacer units. Further increase in number of spacer units (>6) results to an increasing probability of the bending of the spacer chain along with the terminal polar head group more and more towards the liposome surface; this leads to a reduction of the factual distance of the terminal hydrophilic head group from the liposome surface, weakening the response for ConA binding. The threshold concentration or saturation point decreases also with the rigidity of the ground lipid matrix. Increased rigidity of the ground matrix leads to a phase separation and localized 'Domain' formation with the glycolipid inside the ground matrix layer due to their immiscibility, invoking better response resulting to a reduction of required incorporated glycolipid concentration.
Engel
Andreas
A
Department of Pharmacy, Institute of Pharmaceutical Chemistry, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany.
Chatterjee
Swapan K
SK
Al-Arifi
Ali
A
Nuhn
Peter
P
D003208:Concanavalin A / Q000737:chemistry*; D006017:Glycolipids / Q000737:chemistry*; D006027:Glycosides / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D008362:Mannosides / Q000737:chemistry; D008567:Membranes, Artificial; D008968:Molecular Conformation
D006017:Glycolipids; D006027:Glycosides; D008081:Liposomes; D008362:Mannosides; D008567:Membranes, Artificial; D003208:Concanavalin A