Mimicking chitin: Chemical synthesis, conformational analysis, and molecular recognition of the β(1→3) N-acetylchitopentaose analogue

摘要

Mimicking Nature by using synthetic molecules that resemble natural products may open avenues to key knowledge that is difficult to access by using substances from natural sources. In this context, a novel N- acetylchitooligosaccharide analogue, β-1,3-N-acetamido-gluco- pentasaccharide, has been designed and synthesized by using aminoglucose as the starting material. A phthalic group has been employed as the protecting group of the amine moiety, whereas a thioalkyl was used as the leaving group on the reducing end. The conformational properties of this new molecule have been explored and compared to those of the its chito analogue, with the β-1,3 linkages, by a combined NMR spectroscopic/molecular modeling approach. Furthermore, the study of its molecular recognition properties towards two proteins, a lectin (wheat germ agglutinin) and one enzyme (a chitinase) have also been performed by using NMR spectroscopy and docking protocols. There are subtle differences in the conformational behavior of the mimetic versus the natural chitooligosaccharide, whereas this mimetic is still recognized by these two proteins and can act as a moderate inhibitor of chitin hydrolysis.