title: Heteroduplex DNA and ATP induced conformational changes of a MutS mismatch repair protein from Thermus aquaticus.
abstract: ATP hydrolysis by MutS homologues is required for the function of these proteins in mismatch repair. However, the function of ATP hydrolysis in the repair reaction is not very clear. We have examined the role of ATP hydrolysis in oligomerization of Thermus aquaticus (Taq) MutS protein in solution. Analytical gel filtration and cross-linking of MutS protein with disuccinimidyl suburate suggest that TaqMutS is a dimer in the presence of ATP. ATP binding and hydrolysis by TaqMutS reduces the heteroduplex-DNA binding by the protein. Using limited proteolysis we detected extensive conformational changes of the TaqMutS protein in the presence of ATP and heteroduplex DNA. Heteroduplex-DNA binding is necessary for the observed conformational changes since F39A mutant protein defective in DNA binding does not display ATP-induced conformational changes. The implications of the observed conformational changes in the MutS protein are discussed with respect to two different models proposed for the role of ATP hydrolysis by MutS in DNA mismatch repair.
authors.affiliation: Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-1810, USA.
authors.forename: I
authors.initials: I
authors.lastname: Biswas
authors.forename: R
authors.initials: R
authors.lastname: Vijayvargia
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D019943:Amino Acid Substitution / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020137:Base Pair Mismatch / Q000235:genetics; D002850:Chromatography, Gel; D002918:Chymotrypsin / Q000378:metabolism; D003067:Coenzymes / Q000378:metabolism / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019281:Dimerization; D029968:Escherichia coli Proteins; D006868:Hydrolysis; D008970:Molecular Weight; D051719:MutS DNA Mismatch-Binding Protein; D009154:Mutation / Q000235:genetics; D009692:Nucleic Acid Heteroduplexes / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D012996:Solutions; D013388:Succinimides / Q000378:metabolism; D013824:Thermus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D003067:Coenzymes; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D009692:Nucleic Acid Heteroduplexes; D010446:Peptide Fragments; D012996:Solutions; D013388:Succinimides; D000255:Adenosine Triphosphate; D004247:DNA; D002918:Chymotrypsin; D000251:Adenosine Triphosphatases; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli; C019358:disuccinimidyl suberate