| Budget Amount *help |
¥15,530,000 (Direct Cost: ¥14,900,000、Indirect Cost: ¥630,000)
Fiscal Year 2007: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2006: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥9,200,000 (Direct Cost: ¥9,200,000)
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| Research Abstract |
In the present study, we developed 1)photo-responsive DNAs(=artificial DNA devices) that are applicable to the photo-switching of nano-machine,2)photo-fueled molecular tweezers.
Photo-responsive DNA that corresponds to the "engine" of a molecular machine was successfully synthesized on the basis of precise molecular design. The photo-regulatory efficiency of the obtained azobenzene-tethered DNA was three-fold higher than that of our previously reported one : the duplex was largely stabilized in transform and was further destabilized in cis-form with the newly synthesized photo-responsive DNA. Furthermore, we have successfully designed new photo-responsive DNA with reversed switching mode : the duplex was stabilized in cis-form whereas destabilized in trans-form.
By utilizing one of the photo-responsive DNAs synthesized as above, photo-driven molecular machine -molecular tweezers- was developed. In contrast with the previous DNA nano-tweezers that used oligonucleotides as the fuel, our ne
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w nano-tweezers mount photo-responsive DNA as a "photo-engine". In other words, our nano-tweezers are "solar-driven" nano-machine. As exactly designed, the photo-driven nano-tweezers could be opened by irradiating UV light and closed by irradiating visible light.
For the previous DNA nano-tweezers, oligonucleotides were used as the fuel : the mechanical motion was carried out by the hybridization of one DNA fuel to target sequences followed by removing it with another DNA that is completely or partially complementary to the first one. As a result, a duplex. DNA was produced as a waste product in every working cycle. Thus, the operating efficiency decreased gradually with the accumulation of "wastes". In our system, opening and closing are carried out by successive photo-irradiation to the solution involving photoresponsive DNA with UV and visible light that is environmental-friendly and never contaminate the system. For every cycle, almost all the tweezers were closed after visible light irradiation, and the tweezers were open after UV light irradiation. The cycling efficiency did not decrease after open and close of the tweezers for ten times, because no extra oligonucleotides were added. Thus, this molecular machine can be operated semipermanently as long as the DNAs involved are not destroyed. Less
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