title: Activation of human MutS homologs by 8-oxo-guanine DNA damage.
abstract: The DNA lesion 8-oxo-guanine (8-oxo-G) is a highly mutagenic product of the interaction between reactive oxygen species and DNA. To maintain genomic integrity, cells have evolved mechanisms capable of removing this frequently arising oxidative lesion. Mismatch repair (MMR) appears to be one pathway associated with the repair of 8-oxo-G lesions (DeWeese, T. L., Shipman, J. M., Larrier, N. A., Buckley, N. M., Kidd, L. R., Groopman, J. D., Cutler, R. G., te Riele, H., and Nelson, W. G. (1998) Proc. Natl. Acad. Sci. U.S.A. 95, 11915-11920; Ni, T. T., Marsischky, G. T., and Kolodner, R. D. (1999) Mol. Cell 4, 439-444). Here we report the effect of double-stranded DNA oligonucleotides containing a single 8-oxo-G on the DNA binding affinity, ATPase, and ADP right arrow ATP exchange activities of hMSH2-hMSH6 and hMSH2-hMSH3. We found that hMSH2-hMSH6 binds the oligonucleotide DNA substrates with the following affinities: 8-oxo-G/T > 8-oxo-G/G > 8-oxo-G/A > 8-oxo-G/C approximately G/C. A similar trend was observed for DNA-stimulated ATPase and ADP --> ATP exchange activities of hMSH2-hMSH6. In contrast, hMSH2-hMSH3 did not appear to bind any of the 8-oxo-G containing DNA substrates nor was there enhanced ATPase or ADP --> ATP exchange activities. These results suggest that only hMSH2-hMSH6 is activated by recognition of 8-oxo-G lesions. Our data are consistent with the notion that post-replication MMR only participates in the repair of mismatched 8-oxo-G lesions.
authors.affiliation: Genetics and Molecular Biology Program, Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Mazurek
authors.forename: Mark
authors.initials: M
authors.lastname: Berardini
authors.forename: Richard
authors.initials: R
authors.lastname: Fishel
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D029968:Escherichia coli Proteins; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D051379:Mice; D008969:Molecular Sequence Data; D000070956:MutL Proteins; D051719:MutS DNA Mismatch-Binding Protein; D009153:Mutagens; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D011485:Protein Binding; D013379:Substrate Specificity; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C074770:MutL protein, E coli; D009153:Mutagens; C024829:8-hydroxyguanine; D006147:Guanine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; D000070956:MutL Proteins; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli; D010100:Oxygen