Supramolecular design of biomaterials: Great mobility of ligands in polyrotaxanes contributes to enhanced multivalent interaction with binding proteins

COLL 408

Masaru Eguchi, Tooru Ooya, and Nobuhiko Yui. School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Tatsunokuchi, Ishikawa, 923-1292, Japan
Three types maltose-polyrotaxane conjugates (% of α-CD threading: 20, 38 and 50) were synthesized, and the effects of both multivalency and supramolecular mobilities were evaluated. The binding affinity of the maltose-polyrotaxane conjugates with concanavalin A (Con A) was investigated by inhibition of hemagglutination (HIA). The binding affinity of maltose-polyrotaxane containing 38% α-CDs threading with 244 maltose goups was 3000 times greater than maltose itself, while that of maltose-poly(acrylic acid) conjugate (Mn: 25000) with 235 maltose groups was about 170 times. The HIA was proportional to the mobility of maltose, which was estimated by spin-spin relaxation time (T2) of maltose C(1) proton in the polyrotaxane. Therefore, it was concluded that mobility of maltose groups along the polyrotaxane structure contributes to enhanced Con A recognition.