ATP-dependent 5'-3' DNA helicase involved in nucleotide excision repair (NER) of DNA. ATP + H2O = ADP + H(+) + phosphate Binds 1 [4Fe-4S] cluster. 4Fe-4S iron-sulfur-binding is required for protein stability and helicase activity. Belongs to the helicase family. RAD3/XPD subfamily.