Open AccessDetection by electron microscopy of photo-induced denaturation in λ DNA
Author(s) -
Robert Stafford,
David P. Allison,
Ronald O. Rahn
Publication year - 1975
Publication title -
nucleic acids research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.008
H-Index - 537
eISSN - 1362-4954
pISSN - 0305-1048
DOI - 10.1093/nar/2.2.143
Subject(s) - thymine , denaturation (fissile materials) , dna , electron microscope , biology , nucleic acid denaturation , biophysics , base pair , pyrimidine dimer , photochemistry , biochemistry , crystallography , chemistry , nuclear chemistry , dna damage , optics , base sequence , physics
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 electron microscopy after fixing in buffered (pH 9.5) formaldehyde solutions at 25 degrees C. The denatured regions observed corresponded to those described by Inman and Schnös (1) who used alkaline denaturation to preferentially destroy thymine-adenine base pairing. In UV-irradiated DNA, pairs of neighboring thymine residues are converted into photodimers; hence, loss of hydrogen bonding most likely occurs in thymine-rich regions and denaturation results. Conceivably, photo-induced denaturation may under some circumstances represent a more convenient method than alkaline denaturation for mapping thymine-rich regions in DNA.