Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Endonuclease from Escherichia coli that acts specifically upon duplex DNA damaged by ultraviolet light, osmium tetroxide, acid, or x-rays

Journal Article · · J. Biol. Chem.; (United States)
OSTI ID:7306927

An endonuclease which is active upon DNA exposed to ultraviolet light at a photoproduct other than thymine dimers has been extensively purified from Escherichia coli. The small (2.7 S) enzyme is active in the presence of EDTA, has a neutral pH optimum, and is inhibited by tRNA and 1 M NaCl. It has no detectable exonuclease, DNA N-glycosidase, or ribonuclease activities. The enzyme also nicks duplex DNA exposed to OsO/sub 4/, x-rays, or acid, but it does not act upon undamaged DNA or irradiated single-stranded DNA. The majority of sites of action in DNA exposed to ultraviolet light or OsO/sub 4/ appear to be alkali-stable, but those in DNA exposed to x-rays or acid are not. The incisions created by the endonuclease contain 5'-phosphate termini. The enzyme is possibly the same as E. coli endonuclease III described by Radman but it is distinguishable from the other endodeoxyribonucleases described from that organism.

Research Organization:
Univ. of California, Berkeley
OSTI ID:
7306927
Journal Information:
J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 252:9; ISSN JBCHA
Country of Publication:
United States
Language:
English