Endonuclease from Escherichia coli that acts specifically upon duplex DNA damaged by ultraviolet light, osmium tetroxide, acid, or x-rays.
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 OsO4, 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 OsO4 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 (Radman, M. (1976) J. Biol. Chem. 251, 1438-1445), but it is distinguishable from the other endodeoxyribonucleases described from that organism.
D001435:Bacteriophages; D001665:Binding Sites; D004279:DNA, Viral / Q000378:metabolism* / Q000528:radiation effects; D003851:Deoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D004720:Endonucleases / Q000302:isolation & purification / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D009691:Nucleic Acid Denaturation; D009992:Osmium; D013045:Species Specificity; D013329:Structure-Activity Relationship; D014466:Ultraviolet Rays; D014965:X-Rays
D004279:DNA, Viral; D009992:Osmium; D003851:Deoxyribonucleases; D004720:Endonucleases