Crystal structure and biochemical analysis of the MutS.ADP.beryllium fluoride complex suggests a conserved mechanism for ATP interactions in mismatch repair.
During mismatch repair ATP binding and hydrolysis activities by the MutS family proteins are important for both mismatch recognition and for transducing mismatch recognition signals to downstream repair factors. Despite intensive efforts, a MutS.ATP.DNA complex has eluded crystallographic analysis. Searching for ATP analogs that strongly bound to Thermus aquaticus (Taq) MutS, we found that ADP.beryllium fluoride (ABF), acted as a strong inhibitor of several MutS family ATPases. Furthermore, ABF promoted the formation of a ternary complex containing the Saccharomyces cerevisiae MSH2.MSH6 and MLH1.PMS1 proteins bound to mismatch DNA but did not promote dissociation of MSH2.MSH6 from mismatch DNA. Crystallographic analysis of the Taq MutS.DNA.ABF complex indicated that although this complex was very similar to that of MutS.DNA.ADP, both ADP.Mg(2+) moieties in the MutS. DNA.ADP structure were replaced by ABF. Furthermore, a disordered region near the ATP-binding pocket in the MutS B subunit became traceable, whereas the equivalent region in the A subunit that interacts with the mismatched nucleotide remained disordered. Finally, the DNA binding domains of MutS together with the mismatched DNA were shifted upon binding of ABF. We hypothesize that the presence of ABF is communicated between the two MutS subunits through the contact between the ordered loop and Domain III in addition to the intra-subunit helical lever arm that links the ATPase and DNA binding domains.
Alani
Eric
E
Department of Molecular Biology and Genetics, 459 Biotechnology Building, Cornell University, Ithaca, NY 14853-2703, USA. eea3@cornell.edu
Lee
Jae Young
JY
Schofield
Mark J
MJ
Kijas
Amanda W
AW
Hsieh
Peggy
P
Yang
Wei
W
D048868:Adaptor Proteins, Signal Transducing; D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D001426:Bacterial Proteins; D020137:Base Pair Mismatch; D001608:Beryllium / Q000494:pharmacology*; D002352:Carrier Proteins / Q000737:chemistry; D003461:Crystallography; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D005459:Fluorides / Q000494:pharmacology*; D005656:Fungal Proteins / Q000737:chemistry; D000070957:MutL Protein Homolog 1; D051719:MutS DNA Mismatch-Binding Protein; D051718:MutS Homolog 2 Protein; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry
D048868:Adaptor Proteins, Signal Transducing; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D005656:Fungal Proteins; C088859:MLH1 protein, S cerevisiae; C098790:MSH6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C035982:beryllium fluoride; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C489751:MSH2 protein, S cerevisiae; D000070957:MutL Protein Homolog 1; D051719:MutS DNA Mismatch-Binding Protein; D051718:MutS Homolog 2 Protein; C497175:MutS protein, E coli; D001608:Beryllium; D005459:Fluorides