title: MutS interaction with mismatch and alkylated base containing DNA molecules detected by optical biosensor.
abstract: An optical biosensor was used to monitor interactions between the Escherichia coli DNA mismatch repair molecule MutS and various immobilized oligonucleotides. While associating poorly with single-stranded DNA, MutS was capable of rapid association/dissociation from homoduplex DNA. The interaction of MutS with oligonucleotide 30-mers containing single site mismatches demonstrated that during the dissociation phase, MutS binding was greatest to a G-G mismatch, followed by G-T > A-A > C-T, A-C. Binding to A-G, T-T and C-C mispairs was marginally higher than that seen between MutS and homoduplex DNA. The ability of MutS to interact with 30-mers containing alkylated bases was also tested. While binding to O6-methyl-G-C, or to O4-methyl-T-A base pairs was similar to that of homoduplex DNA, strong binding was seen to a O6-methyl-G-T mispair. O4-methyl-T-G, however, was poorly recognized by MutS, with relative binding affinity similar to homoduplex DNA, predicting poor in vivo recognition of O4-methyl-T-G by MutS. Interestingly, MutS demonstrated a relatively high affinity for an 1,N6-etheno-A-T containing homoduplex. Thus, in allowing rapid evaluation of interactions between such molecules, the biosensor will be useful to structure-function analyses.
authors.affiliation: Biomedical Research Center, University of British Columbia, Vancouver, Canada.
authors.forename: I
authors.initials: I
authors.lastname: Babic
authors.forename: S E
authors.initials: SE
authors.lastname: Andrew
authors.forename: F R
authors.initials: FR
authors.lastname: Jirik
mesh_terms: D000251:Adenosine Triphosphatases; D000478:Alkylation; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001482:Base Composition; D015374:Biosensing Techniques; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism*; D004268:DNA-Binding Proteins; D003838:Deoxyadenine Nucleotides / Q000737:chemistry / Q000378:metabolism; D003848:Deoxyguanine Nucleotides / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins; D051719:MutS DNA Mismatch-Binding Protein; D009692:Nucleic Acid Heteroduplexes / Q000737:chemistry / Q000378:metabolism*; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D003838:Deoxyadenine Nucleotides; D003848:Deoxyguanine Nucleotides; D029968:Escherichia coli Proteins; D009692:Nucleic Acid Heteroduplexes; D009841:Oligonucleotides; D011994:Recombinant Proteins; D000251:Adenosine Triphosphatases; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli