UvrABC system

NER in bacteria involves only three proteins to carry out the complete process of damage recognition and excision UvrA, UvrB, and UvrC. Owing to its relative simplicity, the UvrABC system has been studied extensively, particularly in E. coli, and serves as a model system for NER [20, 21]. 

The sequence-dependent trend is conserved in the prokaryotic UvrABC system, in which the NER dual-incision efficiency is around 2.4-fold higher for the same 10S (+)-trans-anti-B[a]P-N2-dG adduct in the TG T case than the CG C-II case [124]. Similarly, the G6 G7 duplex is incised more efficiently by a factor of around... 

Excinuclease - A term used to describe the enzymatic cutting of DNA by the uvrABC system. 

Van Houten, B., Croteau, D. L., Della Vecchia, M. J., Wang, H., and Kisker, C. Close-fitting sleeves DNA damage recognition by the UvrABC nuclease system. Mutat. Res. 577, 92-117, 2005. 

The solution structures of DNA duplexes containing the mutagenic lesions of benzo [a] pyrene-dtrihydroxybenz[a] anthracene, aminopyrene-dG, aminofluorene-dG and malondialdehyde-dG derivatives have been reported. In each case the lesion was shown to intercalate into the duplex causing only minimal disruption to the duplex structure. These structures have been used to study the nucleotide excision repair (NER) by the UvrABC nuclease system from E. coli of the bulky purine lesions. ... 

Helicase II, the product of the uvrD gene, is also required, presumably to unwind and remove the excised oligonucleotide, which is ultimately broken down by other enzymes. The UvrABC enzyme is not a classical endonuclease, because it cuts at two distinct sites, so the term excinuclease has been proposed for it, denoting its role in excision repair. This system also repairs DNA damage that results when two strands covalently crosslink to each other. In this case, the two strands are repaired sequentially (one after the other) in order to preserve an intact template strand. 

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