An O6-methylguanine-DNA Methyltransferase-like Protein from Thermus thermophilus Interacts with a Nucleotide Excision Repair Protein

摘要: The major damage to DNA caused by alkylating agents involves the formation of O 6 -methylguanine (O -meG). Almost all species possess -methylguanine-DNA-methyltransferase (Ogt) repair such damage. Ogt repairs -meG lesions in stoichiometric transfer methyl group a cysteine residue its active site (PCHR). Thermus thermophilus HB8 has an homologue, TTHA1564, but this case alanine replaces putative site. To reveal possible function TTHA1564 processing -meG-containing DNA, we characterized biochemical properties TTHA1564. No methyltransferase activity for synthetic could be detected, indicating is alkyltransferase-like protein. Nevertheless, gel shift assays showed that can bind containing with higher affinity (9-fold) than normal (unmethylated) DNA. Experiments using fluorescent oligonucleotide suggested recognizes same mechanism as other Ogts. We then investigated whether functions sensor. Pull-down identified 20 proteins, including nucleotide excision protein UvrA, which interacts Interaction UvrA was confirmed surface plasmon resonance assay. These results suggest involvement pathways.