question: Which enzymes are involved in global genome nucleotide excision repair (GG-NER) in bacteria?
answer: Nucleotide excision repair (NER) is universally used to recognize and remove many types of DNA damage. In eubacteria, the NER system typically consists of UvrA, UvrB, UvrC, the UvrD helicase, DNA polymerase I, and ligase.  Damage recognition during bacterial NER depends upon UvrA, which binds to the damage and loads UvrB onto the DNA. Subsequently, UvrA, UvrB and UvrC form the excinuclease protein UvrABC endonuclease, a multi-enzymatic complex which carries out repair of damaged DNA in sequential manner. In some cases, Cho may be the effective nuclease for NER, rather than UvrC. UvrC nuclease and the short oligonucleotide that contains the DNA lesion are removed from the post-incision complex by UvrD, a superfamily 1A helicase. In gram-positive organisms, PcrA helicase can also displace UvrC and the excised oligonucleotide from a post-incision NER complex.