Repair of DNA: Polypeptide Crosslinks by Human Excision Nuclease

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 103; no. 11; pp. 4056 - 4061
• Main Authors: Reardon, Joyce T., Sancar, Aziz
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 14.03.2006; National Acad Sciences
• Subjects: Amino Acid Sequence; Amino acids; Animals; Base Sequence; Biochemistry; Biological Sciences; CHO Cells; Cricetinae; Cross-Linking Reagents; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA - genetics; DNA - metabolism; DNA damage; DNA repair; DNA Repair - physiology; DNA Repair Enzymes - chemistry; DNA Repair Enzymes - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Enzymes; Escherichia coli - enzymology; Gels; HeLa Cells; Human subjects; Humans; In Vitro Techniques; Kinetics; Lesions; Models, Biological; Peptides; Peptides - chemistry; Peptides - metabolism; Plasmids; Protein Subunits; Substrate Specificity; Xeroderma Pigmentosum Group A Protein - chemistry; Xeroderma Pigmentosum Group A Protein - metabolism
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0600538103

DNA-protein crosslinks are relatively common DNA lesions that form during the physiological processing of DNA by replication and recombination proteins, by side reactions of base excision repair enzymes, and by cellular exposure to bifunctional DNA-damaging agents such as platinum compounds. The mechanism by which pathological DNA-protein crosslinks are repaired in humans is not known. In this study, we investigated the mechanism of recognition and repair of protein-DNA and oligopeptide-DNA crosslinks by the human excision nuclease. Under our assay conditions, the human nucleotide excision repair system did not remove a 16-kDa protein crosslinked to DNA at a detectable level. However, 4-and 12-aa-long oligopeptides crosslinked to the DNA backbone were recognized by some of the damage recognition factors of the human excision nuclease with moderate selectivity and were excised from DNA at relatively efficient rates. Our data suggest that, if coupled with proteolytic degradation of the crosslinked protein, the human excision nuclease may be the major enzyme system for eliminating protein-DNA crosslinks from the genome.