| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
In this study a new allosteric host was designed and synthesized. Allosteric host 1 consists of two 2,2'-bipyridine moieties, two bisphenol A skeletons, and an ammonium moiety. Host 1 binds a Cu(I) ion to give the corresponding tetrahedral complex, pseudocyclophane, which has a binding cavity and the ammonium group in close proximity. In solvent extraction, 1-Cu(I) complex showed a higher affinity toward flavin mononucleotide sodium salt (FMN) than 1. However, meaningful effect of Cu(I) is not found in a similar host, which does not have an ammonium moiety. These results strongly suggest that cooperative interactions between the cavity and the charged moiety of 1-Cu(I) are important for the FMN binding. After extraction of FMN with 1-Cu(I), the guest was moved to the aqueous phase again by the addition of bathocuproine or triethylamine hydrochloride. Bathocuproine strongly binds to Cu(I) to destroy 1-Cu(I) quantitatively. Triethylamine hydrochloride interacts with the guest to inhibit interaction between 1-Cu(I) and the phosphate moiety of the guest. These results indicated that the framework and the ammonium moiety of the pseudocyclophane are important for the recognition of the guest. In addition, the results show that on-and-off control of molecular recognition is achieved by using this system. A similar allosteric recognition of c-AMP was also performed successfully.
We believe that this study provided a new and fundamental way to construct a sophisticated on-and-off system for recognition of complicated organic molecules in artificial systems.
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