Endonuclease Bax1

UniProtKB accession:  Q970I1

Grouped By:  Matching UniProtKB accession

UniProtKB description:  A dual DNA endonuclease probably involved in nucleotide excision repair (NER) (By similarity). The N-terminal nuclease domain (NTD) of the XPB2-Bax1 complex cleaves on one side of a DNA bubble (which presumably mimics DNA damage), while the NUS nuclease domain cleaves the other side, respectively called 5' and 3' nuclease activities (By similarity). Interaction with XPB blocks the NTD nuclease activity (By similarity). Binds to and stimulates the ATPase activity (and probably also helicase activity) of XPB2 (PubMed:21132514, PubMed:32374860). Increases affinity of XPB2 for forked DNA (PubMed:32986831). Does not stimulate the DNA-dependent activity of XPB1 (PubMed:21132514). In an XPB2-Bax1-bubble DNA crystal (12 bp of dsDNA, a 6 base bubble and 6 bp of dsDNA) the short 6 bp arm is unwound (PubMed:32986831). The 2 helicase and the ThM domains of XPB2 with the NTD and CRD domains of Bax1 encircle the DNA, forming a tunnel where the 12 bp dsDNA and the ds-ssDNA junction are located (PubMed:32986831). The ThM domain is wedged between the ssDNA tails, with the 5' ssDNA contacting Bax1 and the 3' ssDNA in a channel in XPB2 (PubMed:32986831). The nuclease domain (NUS) of Bax1 does not contact DNA in the bubble DNA complex (PubMed:32986831).