Abstract
T4 endonuclease V is an enzyme that repairs DNA by cleaving the 5'-side of the thymine base in thymine photo-dimers in a DNA duplex as a pyrimidine dimer glycosylase. The mode of recognition of unusual base pairing between a thymine photo-dimer and adenine base by the enzyme was studied by X-ray analysis.1)
Mutagenesis and carcinogenesis of damaged bases are well known. 7,8-dihydro-8-oxoguanine (8-oxoguanine).2) and pyrimidine photo-dimers3) in c-Ha-ras genes, were investigated by using synthetic genes containing modified nucleotides.
The genes for monoclonal antibodies specific for cyclobutane pyrimidine dimmers, the (6-4) DNA photoproduct and the Dewar isomer, have been coned and the amino acid sequences of the variable domains were determined. Site directed mutagenesis of the scFv's was used to investigate the origin of the binding affinity of the antibody to the DNA lesion.4)
1) Vassylyev, D.G. et al., Cell 83, 773-782 (1995).
2) Kamiya, H. et al., Cancer Res 52, 3483-3485 (1992b)
3) Kamiya, H. et al., Nucleic Acids Res 21, 2355-2361 (1993).
4) Kobayasi, H. et al., Biochemistry 38,532-539 (1998)
