The MutL ATPase is required for mismatch repair
| Autor: | Paul Modrich, Claudia Spampinato |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
DNA Repair
Base Pair Mismatch Biochemistry Endonuclease MutL Proteins Adenosine Triphosphate Bacterial Proteins Mutant protein MutS-1 Escherichia coli Nucleotide Molecular Biology chemistry.chemical_classification Adenosine Triphosphatases biology Escherichia coli Proteins Hydrolysis Wild type Helicase Cell Biology Molecular biology chemistry biology.protein DNA mismatch repair Protein Binding |
| Zdroj: | The Journal of biological chemistry. 275(13) |
| ISSN: | 0021-9258 2498-2504 |
| Popis: | Members of the MutL family contain a novel nucleotide binding motif near their amino terminus, and the Escherichia coli protein has been found to be a weak ATPase (Ban, C., and Yang, W. (1998) Cell 95, 541-552). Genetic analysis has indicated that substitution of Lys for Glu-32 within this motif of bacterial MutL results in a strong dominant negative phenotype (Aronshtam, A., and Marinus, M. G. (1996) Nucleic Acids Res. 24, 2498-2504). By in vitro comparison of MutL-E32K with the wild type protein, we show the mutant protein to be defective in DNA-activated ATP hydrolysis, as well as MutS- and MutL-dependent activation of the MutH d(GATC) endonuclease and the mismatch repair excision system. MutL-E32K also acts in dominant negative manner in the presence of wild type MutL in vitro, inhibiting the overall mismatch repair reaction, as well as MutH activation. As judged by protein affinity chromatography, MutL and MutL-E32K both support formation of ternary complexes that also contain MutS and MutH or MutS and DNA helicase II. These findings imply that the MutL nucleotide binding center is required for mismatch repair and suggest that the dominant negative behavior of the MutL-E32K mutation is due to the formation of dead-end complexes in which the MutL-E32K protein is unable to transduce a signal from MutS that otherwise results in mismatch-dependent activation of the MutH d(GATC) endonuclease or the unwinding activity of helicase II. |
| Databáze: | OpenAIRE |
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