Elucidation of Glycan Functions Based on Precise Synthesis

Abstract

Glycoconjugates, such as glycolipids and glycoproteins, are widely distributed from microorganisms to plants and animals and are involved in many basic biological events. However, their scarcity and diversity make it difficult to obtain pure samples, thereby hampering their elucidation. Supplying structurally defined molecules based on organic synthesis is a powerful tool for clarifying their functions at the molecular level. In this review, several synthetic approaches that the author has been engaged are introduced. The efficient synthesis of gangliosides was achieved by the development of an intramolecular ceramide introduction reaction. A combination of appropriate deprotection and glycosylation reactions enabled rapid glycan synthesis, and a high-mannose-type glycan library was constructed using chemo-enzymatic approaches. Structure-activity relationship studies of the bacterial glycolipid MPIase have uncovered the mechanism of membrane protein integration in Escherichia coli.