Inhibition of Msh6 ATPase activity by mispaired DNA induces a Msh2(ATP)-Msh6(ATP) state capable of hydrolysis-independent movement along DNA.
The Msh2-Msh6 heterodimer plays a key role in the repair of mispaired bases in DNA. Critical to its role in mismatch repair is the ATPase activity that resides within each subunit. Here we show that both subunits can simultaneously bind ATP and identify the Msh6 subunit as containing the high-affinity ATP binding site and Msh2 as containing a high-affinity ADP binding site. Stable binding of ATP to Msh6 causes decreased affinity of Msh2 for ADP, and binding to mispaired DNA stabilized the binding of ATP to Msh6. Our results support a model in which mispair binding encourages a dual-occupancy state with ATP bound to Msh6 and Msh2; this state supports hydrolysis-independent sliding along DNA.
Mazur
Dan J
DJ
Ludwig Institute for Cancer Research, CMME 3058, 9500 Gilman Drive, La Jolla, California 92093, USA.
Mendillo
Marc L
ML
Kolodner
Richard D
RD
D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D019943:Amino Acid Substitution; D020137:Base Pair Mismatch; D001665:Binding Sites; D003432:Cross-Linking Reagents; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D006868:Hydrolysis; D051718:MutS Homolog 2 Protein / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism
D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; C098790:MSH6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; C489751:MSH2 protein, S cerevisiae; D051718:MutS Homolog 2 Protein