| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Polyvalent interactions between cell-surface carbohydrates and various proteins form the basis of recognition events that are fundamental to a diverse range of biological processes. Oligosaccharides are very complex and diverse, which makes their synthesis both labor-intensive and time-consuming. As a result, understanding biological functions of oligosaccharides is a complicated problem. The synthesis of oligosaccharides by solid-phase approach offers a feasible solution to the problem In our solid-phase synthesis, the saccharides are attached to resins through a silyl ether bond at the non-reducing end of sugar. We have found that the selection of hydroxyl protecting groups is important for controlling the reactivity of both glycosyl donors and acceptors, and glycosylation of the armed thioglycosides or glycosyl fluorides with armed glycosyl acceptors gave coupling products with high yields. We have examined a new method for the construction of complex oligosaccharides on the solid p
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hase based on one-pot glycosylation and orthogonal glycosylation, and its application to the synthesis of the heptasaccharide phytoalexin elicitor. One-pot glycosylation of glycosyl bromide, ethylthioglycoside, and phenylthioglycoside in solution phase provided common carbohydrate building block, which was converted to both glycosyl fluoride and thioglycoside. After glycosyl fluoride was attached to resins, orthogonal glycosylation of the glycosyl fluoride and thioglycoside on solid phase was carried out to give phytoalexin elicitor. Using this methodology, we have prepared oligosaccharide as large as heptasaccharides on solid supports. For a detailed description of the three dimensional structure of a carbohydrate molecules, a number of aspects should be addressed, namely, its conformation, flexibility, dynamics, hydrophilic vs hydrophobic properties. A powerful approach to studies of these molecules is to combine information from computer simulations with experimental data. We have developed a useful and reliable method for the conformational analysis of a flexible oligosaccharides in water using combination of molecular dynamics simulations and chemical shift simulations. Less
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