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"Effect of amino acid substitutions in the rad50 ATP binding domain on DNA double strand break repair in yeast." |
Chen L, Trujillo KM, Van Komen S, Roh DH, Krejci L, Lewis LK, Resnick MA, Sung P, Tomkinson AE |
Published Feb. 28, 2005 in J Biol Chem volume 280 .
Pubmed ID: 15546877
Abstract:
| The Saccharomyces cerevisiae Rad50-Mre11-Xrs2 complex plays a central role in the cellular response to DNA double strand breaks. Rad50 has a globular ATPase head domain with a long coiled-coil tail. DNA binding by Rad50 is ATP-dependent and the Rad50-Mre11-Xrs2 complex possesses DNA unwinding and endonuclease activities that are regulated by ATP. Here we have examined the role of the Rad50 Walker type A ATP binding motif in DNA double strand break repair by a combination of genetic and biochemical approaches. Replacement of the conserved lysine residue within the Walker A motif with alanine, glutamate, or arginine results in the same DNA damage sensitivity and homologous recombination defect as the rad50 deletion mutation. The Walker A mutations also cause a deficiency in non-homologous end-joining. As expected, complexes containing the rad50 Walker A mutant proteins are defective in ATPase, ATP-dependent DNA unwinding, and ATP-stimulated endonuclease activities. Although the DNA end-bridging activity of the Rad50-Mre11-Xrs2 complex is ATP-independent, the end-bridging activity of complexes containing the rad50 Walker A mutant proteins is salt-sensitive. These results provide a molecular explanation for the observed in vivo defects of the rad50 Walker mutant strains and reveal a novel ATP-independent function for Rad50 in DNA end-bridging. |
This publication refers to following REPAIRtoire entries:
| Genes |
Last modification of this entry: Oct. 6, 2010
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