title: An archaeal XPF repair endonuclease dependent on a heterotrimeric PCNA.
abstract: Archaea share many similarities with eukarya in their information processing pathways and have proven to be a useful model for studies of DNA replication and transcription, but DNA repair pathways are not well understood in archaea. Nucleotide Excision Repair (NER) deals with many bulky DNA lesions and involves over 30 proteins in eukarya. Archaeal NER has not been characterized biochemically, but homologues of the human repair nucleases XPF and XPG have been identified by homology searches. Crenarchaeal XPF proteins have a simplified domain structure, consisting of the C-terminal nuclease domain conserved in XPF and Mus81 but lacking the N-terminal 'helicase' domain that is found in eukaryal and euryarchaeal sequences. Unexpectedly, Sulfolobus XPF is only active in the presence of the sliding clamp PCNA, which is a heterotrimer in this organism. Interactions with two of the three subunits of PCNA are mediated via a C-terminal interaction motif. The PCNA-XPF complex acts as a structure-specific nuclease on a similar range of DNA flap, bubble and junction substrates as the human protein, suggesting a fundamental conservation through billions of years of evolution.
authors.affiliation: Centre for Biomolecular Science, St Andrews University, North Haugh, St Andrews, Fife KY16 9ST, UK.
authors.forename: J A
authors.initials: JA
authors.lastname: Roberts
authors.forename: S D
authors.initials: SD
authors.lastname: Bell
authors.forename: M F
authors.initials: MF
authors.lastname: White
mesh_terms: D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D004249:DNA Damage; D004260:DNA Repair; D019641:DNA, Archaeal / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004720:Endonucleases; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D016944:Sulfolobus / Q000201:enzymology* / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D019641:DNA, Archaeal; D004268:DNA-Binding Proteins; D018809:Proliferating Cell Nuclear Antigen; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; C095888:xeroderma pigmentosum group F protein; D004720:Endonucleases; C498772:MUS81 protein, human