Abstract
Two heteroduplexes d(C1A2C3T4C5G6C7A8C9A10C11)-d (G12T13G14T15G16G17A18G19T20G21) containing a bulged guanine either unmodified or modified with the carcinogen N-2-acetylaminofluorene (AAF) have been studied by nuclear magnetic resonance (NMR) as models of slipped mutagenic intermediates (SMI). Conformational equilibria are observed in both the unmodified and the AAF-modified heteroduplexes. The major conformation of the unmodified duplex is one where the extra guanine is stacked in the helix and the major conformation of the AAF-modified heteroduplex is one where the AAF is external to the helix. Unusual sugar proton chemical shifts of C5- and G6-AAF indicate that the AAF ring is pointing out in the 5' direction. A strong increase in the modified heteroduplex melting temperature (+15 degrees C) is observed. Moreover, in contrast to the unmodified heteroduplex, which shows extensive melting in the vicinity of the bulged guanine, the base pairs around the bulge in the AAF-modified heteroduplex remain paired at temperatures up to 30 degrees C. This exceptional stability of the site around the bulged modified guanine is suggested to be responsible for the high rate of -1 mutation induced by AAF at repetitive sequences.
Full text
PDF![4646](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ec9c/308513/c685fa356b46/nar00046-0104.png)
![4647](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ec9c/308513/b952f15d4803/nar00046-0105.png)
![4648](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ec9c/308513/56edf6fd42a6/nar00046-0106.png)
![4649](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ec9c/308513/e41af13fdd51/nar00046-0107.png)
![4650](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ec9c/308513/73e318745cca/nar00046-0108.png)
![4651](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ec9c/308513/9231db4a8b55/nar00046-0109.png)
![4652](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/ec9c/308513/ec8de23ec846/nar00046-0110.png)
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cho B. P., Beland F. A., Marques M. M. NMR structural studies of a 15-mer DNA duplex from a ras protooncogene modified with the carcinogen 2-aminofluorene: conformational heterogeneity. Biochemistry. 1994 Feb 15;33(6):1373–1384. doi: 10.1021/bi00172a013. [DOI] [PubMed] [Google Scholar]
- Eckel L. M., Krugh T. R. 2-Aminofluorene modified DNA duplex exists in two interchangeable conformations. Nat Struct Biol. 1994 Feb;1(2):89–94. doi: 10.1038/nsb0294-89. [DOI] [PubMed] [Google Scholar]
- Evans F. E., Miller D. W., Levine R. A. 1H NMR study of self-association and restricted internal rotation of the C8-substituted deoxyguanosine 5'-monophosphate adduct of the carcinogen 2-(acetylamino)fluorene. J Biomol Struct Dyn. 1986 Apr;3(5):935–948. doi: 10.1080/07391102.1986.10508475. [DOI] [PubMed] [Google Scholar]
- Garcia A., Lambert I. B., Fuchs R. P. DNA adduct-induced stabilization of slipped frameshift intermediates within repetitive sequences: implications for mutagenesis. Proc Natl Acad Sci U S A. 1993 Jul 1;90(13):5989–5993. doi: 10.1073/pnas.90.13.5989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kalnik M. W., Norman D. G., Li B. F., Swann P. F., Patel D. J. Conformational transitions in thymidine bulge-containing deoxytridecanucleotide duplexes. Role of flanking sequence and temperature in modulating the equilibrium between looped out and stacked thymidine bulge states. J Biol Chem. 1990 Jan 15;265(2):636–647. [PubMed] [Google Scholar]
- Koehl P., Valladier P., Lefèvre J. F., Fuchs R. P. Strong structural effect of the position of a single acetylaminofluorene adduct within a mutation hot spot. Nucleic Acids Res. 1989 Dec 11;17(23):9531–9541. doi: 10.1093/nar/17.23.9531. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Koffel-Schwartz N., Verdier J. M., Bichara M., Freund A. M., Daune M. P., Fuchs R. P. Carcinogen-induced mutation spectrum in wild-type, uvrA and umuC strains of Escherichia coli. Strain specificity and mutation-prone sequences. J Mol Biol. 1984 Jul 25;177(1):33–51. doi: 10.1016/0022-2836(84)90056-1. [DOI] [PubMed] [Google Scholar]
- Lambert I. B., Napolitano R. L., Fuchs R. P. Carcinogen-induced frameshift mutagenesis in repetitive sequences. Proc Natl Acad Sci U S A. 1992 Feb 15;89(4):1310–1314. doi: 10.1073/pnas.89.4.1310. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lindsley J. E., Fuchs R. P. Use of single-turnover kinetics to study bulky adduct bypass by T7 DNA polymerase. Biochemistry. 1994 Jan 25;33(3):764–772. doi: 10.1021/bi00169a018. [DOI] [PubMed] [Google Scholar]
- Marion D., Wüthrich K. Application of phase sensitive two-dimensional correlated spectroscopy (COSY) for measurements of 1H-1H spin-spin coupling constants in proteins. Biochem Biophys Res Commun. 1983 Jun 29;113(3):967–974. doi: 10.1016/0006-291x(83)91093-8. [DOI] [PubMed] [Google Scholar]
- O'Handley S. F., Sanford D. G., Xu R., Lester C. C., Hingerty B. E., Broyde S., Krugh T. R. Structural characterization of an N-acetyl-2-aminofluorene (AAF) modified DNA oligomer by NMR, energy minimization, and molecular dynamics. Biochemistry. 1993 Mar 16;32(10):2481–2497. doi: 10.1021/bi00061a005. [DOI] [PubMed] [Google Scholar]
- Rajagopalan M., Rahmouni A. R., Wells R. D. Flanking AT-rich tracts cause a structural distortion in Z-DNA in plasmids. J Biol Chem. 1990 Oct 5;265(28):17294–17299. [PubMed] [Google Scholar]
- Streisinger G., Okada Y., Emrich J., Newton J., Tsugita A., Terzaghi E., Inouye M. Frameshift mutations and the genetic code. This paper is dedicated to Professor Theodosius Dobzhansky on the occasion of his 66th birthday. Cold Spring Harb Symp Quant Biol. 1966;31:77–84. doi: 10.1101/sqb.1966.031.01.014. [DOI] [PubMed] [Google Scholar]
- Venditti S., Wells R. D. A DNA conformational alteration induced by a neighboring oligopurine tract on GAATTA enables nicking by EcoRI. J Biol Chem. 1991 Sep 5;266(25):16786–16790. [PubMed] [Google Scholar]
- Woodson S. A., Crothers D. M. Structural model for an oligonucleotide containing a bulged guanosine by NMR and energy minimization. Biochemistry. 1988 May 3;27(9):3130–3141. doi: 10.1021/bi00409a004. [DOI] [PubMed] [Google Scholar]