Some XP proteins are
	• XPA, which encodes a protein that binds the damaged site and helps assemble the other proteins needed for NER. •  XPB and XPD, which are part of TFIIH. Some mutations in XPB and XPD also produce signs of premature aging. • XPF, with ERCC1 cuts the backbone on the 5' side of the damage • XPG, which cuts the backbone on the 3' side. • XPC interacts with HR23B in GGR and recognizes damage • XPD is a DNA helicase in in transcription complex • VPV is a by-pass polymerase