Recognition of Novel Amphiphiles with Many Pendent Mannose Residues by Con A

Abstract

Novel amphiphiles which carry many mannose residues as side chains were prepared by telomerization of N-methacryloylaminopropyl D-mannopyranoside (alpha:beta = 20:1), N-methacryloylaminohexyl D-mannopyranoside (alpha:beta = 20:1), or 3-(2-methacryloylaminoethylthio)propyl D-mannopyranoside (alpha:beta = 4:1) using a lipophilic radical initiator. The mannose-carrying amphiphiles incorporated in liposomes were recognized by a lectin from Canavalia ensiformis (Con A), which was proven by the increase in turbidity of the liposome suspension after mixing with Con A. The interaction between sugar residues on the liposome surface and the lectin was largely affected by the degree of polymerization (DP) and the surface density of the amphiphile in the liposomes. The distance between the sugar residues and the polymer main chain did not affect the specific recognition by the lectin significantly in the liposome system, whereas it appreciably affected the recognition in the water-soluble polymer system. The association constants (Ka) of the amphiphiles (DP approximately 18) with Con A (0.3-2.2 x 10(6) M-1 at 25 degrees C) were much larger than that of alpha-methyl D-mannopyranoside (8.2 x 10(3) M-1) due to the "cluster effect ". The positive entropy change (20-52 J/mol K) for the binding of Con A to mannose residues on the liposome surface showed that the recognition in the liposome system was largely promoted by the release of water molecules from both the sugar residues on the liposome surface and the binding site of Con A.

Interaction of wheat germ agglutinin with an N-acetylglucosamine-carrying telomer brush accumulated on a colloidal gold monolayer

“…An azo-type radical initiator with dioctadecyl groups at both ends (DODA-501, Scheme 1(A)) [45][46][47][48] and the disulfidecarrying photo-iniferter (Cys-BDC, Scheme 1(B)) [23] were prepared as described earlier. A polymerizable phospholipid (bis(trans, trans-2,4-dioctadecadienoyl)phosphatidyl choline, DDPC) and 3-aminopropyl triethoxysilane (APTS) were purchased from Japan Fat & Oil Co., Tokyo, Japan and ShinEtsu Chemicals, Tokyo, Japan, respectively.…”

“…1(B)) [46][47][48]. The turbidity change of GlcNAc-carrying liposomes caused by the addition of WGA was dependent on the DP value of DODA-PMHGlcNAc: The addition of WGA to the dispersion of DODA-PMHGlcNAc (DP = 19) liposome induced a gradual increase in turbidity at 350 nm.…”

“…1-(6 -Methacryloylaminohexyl)-2-N-acetoamido-2-deoxy-d-glucopyranoside (MHGlcNAc) was prepared from N-acetylglucosamine (GlcNAc) and 6-hydroxyhexyl methacrylamide by following the synthetic procedure for 1-(6 -methacryloylaminohexyl)-d-mannopyranoside (MHMan) (see Supplementary Materials) [47]. The chemical structure of the monomer was confirmed by 1 H NMR (400 MHz, DX-400, JEOL, Tokyo, Japan).…”

“…), it has often been reported that a lectin does not bind to an incorporated sugar-carrying amphiphile with a short spacer group between the sugar residue and a hydrophobic anchor [46][47][48], due to a large steric hindrance preventing the huge lectin from approaching the small sugar residue on the membrane surface. Therefore, CysPMHGlcNAc, which has a telomer chain with many pendent GlcNAc groups, was adopted as a "fly" to fish for WGA in this study.…”

Self-association of zwitterionic polymer–lipid conjugates in water as examined by scattering measurements

“…Since lipids are natural compounds, they have a great advantage in biomedical use (e.g., as drug carriers). In fact, there have been many studies on the properties and functions of biomaterials containing natural or synthetic lipids [8][9][10][11][12]. Furthermore, 2-methacryloyloxyethylphosphorylcholine (MPC), a zwitterionic vinyl monomer analogous to a phosphorylcholine head group of a natural lipid, has been copolymerized with apolar monomers such as n-butyl methacrylate to afford excellent biocompatible properties such as resistance against non-specific protein adsorption, cell adhesion, and thrombus formation [13][14][15].…”