| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Hinge motions play crucial roles in the functions of motor proteins, signal transducers, and allosteric enzymes. Thus, mimicking the hinge regions of these natural molecular machines with small molecules is the basis for the construction of smaller molecular machines and devices. We brought β-xylopyranosides into focus as potential hinge molecules, because these molecules are prone to undergo a ring-flip, which accompanies the conversion of the all equatorial substituents into axial orientations in a pliers-like manner. The same ring-flip is more difficult with the corresponding substituted-cyclohexanes because of the lack of anomeric effect and the existence of an additional axial hydrogen atom. In our continuing efforts to create molecular devices from xylopyranosides, we invented "hinge sugars," 2,4-diamino-2,4-dideoxy-β-xylopyranosides, which shifts the conformation from C1 to 1C in response to a metal ion. In this stucy, we were able to fix this hinge sugar in 1C conformation by forming a Pt^<2+> complex or by N,N'-carbonylation. With this hinge sugar in hand, we were also able to build a metal ion sensor, 1,3-dipyrenylmethyl-hmge sugar. Chelation of the diamino group to the metal ion causes the ring flip of hinge sugar, leading the diequatorial pyrenyl groups into the diaxial orientations. The parallel pyrene groups afford an excimer fluorescence. These findings are important for the construction of molecular machines and molecular devices in the future.
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