Abstract
The transfectivity of anthramycin (Atm)-modified φX174 replicative form (RF) DNA in Escherichia coli is lower in uvrA and uvrB mutant cells but much higher in uvrC mutant cells compared to wild-type cells. Pretreatment of the Atm-modified phage DNA with purified UVRA and UVRB significantly increases the transfectivity of the DNA in uvrA or uvrB mutant cells. This pretreatment greatly reduces the UVRABC nuclease-sensitive sites (UNSS) and Atm-induced absorbance at 343 nm in the Atm-modified DNA without producing apurinic sites. The reduction of UNSS is proportional to the concentrations of UVRA and UVRB and the enzyme-DNA incubation time and requires ATP. We conclude that there are two different mechanisms for repairing Atm-N2 guanine adducts by UVR proteins: (1) UVRA and UVRB bind to the Atm-N2 guanine double-stranded DNA region and consequently release the Atm from the adducted guanine; (2) UVRABC makes an incision at both sides of the Atm-DNA adduct. The latter mechanism produces potentially lethal double-strand DNA breaks in Atm-modified φX174 RF DNA in vitro.
Original language | English (US) |
---|---|
Pages (from-to) | 855-866 |
Number of pages | 12 |
Journal | Journal of Molecular Biology |
Volume | 220 |
Issue number | 4 |
DOIs | |
State | Published - Aug 20 1991 |
Externally published | Yes |
Keywords
- DNA-damage
- UVR
- anthramycin
- repair
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology