| Summary: | 碩士 === 國立臺北科技大學 === 化學工程系碩士班 === 92 === Science the helix structure of double strand DNA was discovered by James Watson and Francis Crick in 1953 .Pepole learned more about the biological relating molecules , and interested in the DNA’s conductivity .
Contributed by several research teams , the conductivity of DNA was disclosed and understood. Accordingly , DNA’s conducting ability was attributed to the distance between Guanunes . Depend on the Marcus Theory and the rule that Guanine is the only base which provides transferring an electron , the distance between G and C base pairs must be maintained among less than 10~15 Å . Besides , the vertical distance between 2 bases in DNA is 3.4 Å , so the space of each GC base pair could load only 2~3 AT base pairs ideally.
In this thesis , the goal DNA fragments were obtained by sequencing the base pairs via the FORTRAN program designed by us , We got two observations after checking the DNA sequences of Streptomyces coelicolor A3(2) , one is the space between GC base pairs can load 3 AT base pairs (the longest fragment 26527 bps) , the distance is about 9 μm . the other is the space between GC base pairs can load 2 AT base pairs (The longest fragment 5413 bps), The distance is about 1.8 μm .At the mean time , we purified the chromosome of S.C A3(2) and amplify the goal DNA fragments by PCR .For the fragments which GC can load 2 AT base pairs , We digested by restriction enzyme and ligation process to magnify the DNA length to 2.2~2.3 μm.
Finally , the goal DNA fragments were fixed to the both ends of the microelectrode , and measured the current passed by the DNA . the amount of DNA were further examined by the Atomic Force Microscopy (AFM) to obtain the single DNA conductivity .
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