PHOTOELECTRIC BEHAVIOR OF SUPERCOILED DNA AND ITS APPLICATIONS IN MOLECULAR-BIOLOGY

In this paper, the photoelectric behavior of supercoiled DNA was studi ed by using a transparent electrode of indium-tin oxide-coated borosil icate (ITO) technology. The supercoiled DNA responsed a negative photo electric current pulse to the light of 320-410 nm, even in pure water, which was an experimental proof for electron transfer along DNA doubl e helix. We found that the photoelectric current behaved a decrease wh en the supercoiled DNA subjected to the UV light, and that the photoel ectric current decreasing was in accordance with the biological cleava ge of the supercoiled DNA. We assumed that the photo-cleavage of super coiled DNA was related to its oxidative damage through the long-range electron transfer. This photoelectric method can be used to capture th e photo-cleavage dynamic information of supercoiled DNA in a real time and in a continuous fashion. (C) 1998 Elsevier Science S.A. All right s reserved.