Thermodynamic stability of base pairs between 2-hydroxyadenine and incoming nucleotides as a determinant of nucleotide incorporation specificity during replication.
We investigated the thermodynamic stability of double-stranded DNAs with an oxidative DNA lesion, 2-hydroxyadenine (2-OH-Ade), in two different sequence contexts (5'-GA*C-3' and 5'-TA*A-3', A* represents 2-OH-Ade). When an A*-N pair (N, any nucleotide base) was located in the center of a duplex, the thermodynamic stabilities of the duplexes were similar for all the natural bases except A (N = T, C and G). On the other hand, for the duplexes with the A*-N pair at the end, which mimic the nucleotide incorporation step, the stabilities of the duplexes were dependent on their sequence. The order of stability is T > G > C >> A in the 5'-GA*C-3' sequences and T > A > C > G in the 5'-TA*A-3' sequences. Because T/G/C and T/A are nucleotides incorporated opposite to 2-OH-Ade in the 5'-GA*C-3' and 5'-TA*A-3' sequences, respectively, these results agree with the tendency of mutagenic misincorporation of the nucleotides opposite to 2-OH-Ade in vitro. Thus, the thermodynamic stability of the A*-N base pair may be an important factor for the mutation spectra of 2-OH-Ade.
Kawakami
J
J
Department of Chemistry, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan.
Kamiya
H
H
Yasuda
K
K
Fujiki
H
H
Kasai
H
H
Sugimoto
N
N
D020029:Base Pairing / Q000528:radiation effects; D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D006147:Guanine / Q000378:metabolism*; D008958:Models, Molecular; D016296:Mutagenesis / Q000235:genetics*; D009691:Nucleic Acid Denaturation / Q000528:radiation effects; D009711:Nucleotides / Q000235:genetics / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D013379:Substrate Specificity; D013698:Templates, Genetic; D013816:Thermodynamics; D014466:Ultraviolet Rays
D009711:Nucleotides; D009838:Oligodeoxyribonucleotides; D006147:Guanine; D004247:DNA; C008183:isoguanine; D004259:DNA-Directed DNA Polymerase