title: Cloning and expression of the cDNA encoding the human homologue of the DNA repair enzyme, Escherichia coli endonuclease III.
abstract: We previously purified a bovine pyrimidine hydrate-thymine glycol DNA glycosylase/AP lyase. The amino acid sequence of tryptic bovine peptides was homologous to Escherichia coli endonuclease III, theoretical proteins of Saccharomyces cerevisiae and Caenorhabditis elegans, and the translated sequences of rat and human 3'-expressed sequence tags (3'-ESTs) (Hilbert, T. P., Boorstein, R. J., Kung, H. C., Bolton, P. H., Xing, D., Cunningham, R. P., Teebor, G. W. (1996) Biochemistry 35, 2505-2511). Now the human 3'-EST was used to isolate the cDNA clone encoding the human enzyme, which, when expressed as a GST-fusion protein, demonstrated thymine glycol-DNA glycosylase activity and, after incubation with NaCNBH3, became irreversibly cross-linked to a thymine glycol-containing oligodeoxynucleotide, a reaction characteristic of DNA glycosylase/AP lyases. Amino acids within the active site, DNA binding domains, and [4Fe-4S] cluster of endonuclease III are conserved in the human enzyme. The gene for the human enzyme was localized to chromosome 16p13.2-.3. Genomic sequences encoding putative endonuclease III homologues are present in bacteria, archeons, and eukaryotes. The ubiquitous distribution of endonuclease III-like proteins suggests that the 5,6-double bond of pyrimidines is subject to oxidation, reduction, and/or hydration in the DNA of organisms of all biologic domains and that the resulting modified pyrimidines are deleterious to the organism.
authors.affiliation: Department of Pathology and Kaplan Comprehensive Cancer Center, New York University Medical Center, New York, New York 10016, USA.
authors.forename: T P
authors.initials: TP
authors.lastname: Hilbert
authors.forename: W
authors.initials: W
authors.lastname: Chaung
authors.forename: R J
authors.initials: RJ
authors.lastname: Boorstein
authors.forename: R P
authors.initials: RP
authors.lastname: Cunningham
authors.forename: G W
authors.initials: GW
authors.lastname: Teebor
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry; D001483:Base Sequence; D002417:Cattle; D002885:Chromosomes, Human, Pair 16; D003001:Cloning, Molecular; D004260:DNA Repair; D018076:DNA, Complementary / Q000235:genetics; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004706:Endodeoxyribonucleases / Q000235:genetics*; D004926:Escherichia coli / Q000201:enzymology; D029968:Escherichia coli Proteins; D005656:Fungal Proteins / Q000737:chemistry; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D018076:DNA, Complementary; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; D012333:RNA, Messenger; D004706:Endodeoxyribonucleases; D043224:Deoxyribonuclease (Pyrimidine Dimer); C106403:NTH protein, E coli