Binding specificities of the mismatch binding protein, MutS, to oligonucleotides containing modified bases.
We have studied the effects of DNA mismatch repair on mutagenesis induced by nucleoside analogs. Among them, the mutagenic action of 3,4-dihydro-6H,8H-pyrimido[4,5-c][1,2]oxazin-7-one 2'-deoxyriboside (dP) showed high susceptibility to the mismatch repair system, while mutagenesis by N4-aminocytidine and N4-hydroxycytidine was only weakly affected. 2-Aminopurine mutagenesis showed intermediate susceptibility. MutS protein specifically bound to an oligonucleotide duplex containing a dP-dG pair, while the dP-dA pair was bound only weakly. The binding to the dP-dG pair was as strong as binding to a dA-dC mismatch. These specific binding properties can explain the effective avoidance of dP-induced mutagenesis by the mismatch repair system. We have also studied the effects of the repair system on mutagenesis induced by methylating and ethylating agents.
Negishi
K
K
Gene Research Center, Okayama University.
Maehara
D
D
Nakamura
S
S
Loakes
D
D
Worth
L
L
Schaaper
R M
RM
Seio
K
K
Sekine
M
M
Negishi
T
T
D015075:2-Aminopurine / Q000737:chemistry; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins; D020137:Base Pair Mismatch; D001483:Base Sequence; D003562:Cytidine / Q000031:analogs & derivatives* / Q000737:chemistry; D004268:DNA-Binding Proteins; D003853:Deoxyribonucleosides / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000378:metabolism*; D051719:MutS DNA Mismatch-Binding Protein; D009692:Nucleic Acid Heteroduplexes / Q000737:chemistry* / Q000378:metabolism*; D009841:Oligonucleotides / Q000737:chemistry* / Q000378:metabolism*
C115248:2'-deoxy-ribofuranosyl-(3,4-dihydro-6H,8H-pyrimido(4,5-c)(1,2)oxazin-7-one); D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D003853:Deoxyribonucleosides; D029968:Escherichia coli Proteins; D009692:Nucleic Acid Heteroduplexes; D009841:Oligonucleotides; D015075:2-Aminopurine; C038769:N(4)-aminocytidine; D003562:Cytidine; C010737:N(4)-hydroxycytidine; D000251:Adenosine Triphosphatases; D051719:MutS DNA Mismatch-Binding Protein; C497175:MutS protein, E coli