Detection by electron microscopy of photo-induced denaturation in λ DNA

摘要: We have used an electron microscope to study localized denatured regions in ultraviolet-irradiated DNA. DNA from bacteriophage lambda was UV-irradiated and then prepared for microscopy after fixing buffered (pH 9.5) formaldehyde solutions at 25 degrees C. The observed corresponded those described by Inman Schnos (1) who alkaline denaturation preferentially destroy thymine-adenine base pairing. In DNA, pairs of neighboring thymine residues are converted into photodimers; hence, loss hydrogen bonding most likely occurs thymine-rich results. Conceivably, photo-induced may under some circumstances represent a more convenient method than mapping