UvrA2

UvrA2 is a second homolog of the UvrA protein found in some bacteria that possess two UvrA genes, commonly referred to as UvrA1 and UvrA2. Like UvrA1, UvrA2 is part of the bacterial nucleotide excision repair (NER) pathway and participates in damage recognition by forming a complex with UvrB to locate DNA lesions caused by ultraviolet light or chemical mutagens.

In the NER process, UvrA2 typically binds ATP and, together with UvrB, patrols DNA for distortions. When a lesion is detected, the UvrA2–UvrB complex facilitates the recruitment of UvrC, which then makes incisions on the damaged DNA strand to initiate repair. The precise functional distinctions between UvrA2 and UvrA1 can vary among organisms; UvrA2 may differ in DNA-binding preferences, interaction with UvrB, or regulatory control, potentially reflecting specialization under different environmental conditions.

Genetically, uvrA2 genes are found in various bacterial lineages that maintain two UvrA paralogs. The genes can be organized in different ways relative to uvrB and uvrC, sometimes within operons and other times as separate transcription units. Expression of UvrA2 may be constitutive or subject to regulation, and in some species could be linked to the SOS response or other stress-inducible pathways.

The presence of UvrA2 highlights diversification within the bacterial NER system and suggests potential adaptations in DNA damage response strategies. Further comparative studies across species seek to clarify when and why organisms retain multiple UvrA homologs and how their roles diverge.

See also: UvrA, UvrB, UvrC, Nucleotide excision repair, SOS response.