Abstract
DNA polymerase beta (pol beta) from rat brain, overexpressed in Escherichia coli, was used as a model to study the factors responsible for substrate specificity [kpol, Kd(app) and kpol/Kd(app)] and fidelity during DNA synthesis. The roles of two active-site residues, Asn-279 and Tyr-271, were examined by construction of N279A, N279Q, Y271A, Y271F and Y271S mutants followed by structural analyses by NMR and CD and functional analyses by pre-steady-state kinetics. The results are summarized as follows. (i) None of the two-dimensional NMR spectra of the mutants was significantly perturbed relative to that for wild-type pol beta, suggesting that Tyr-271 and Asn-279 are not important for the global structure of the protein. (ii) CD analyses of guanidinium hydrochloride-induced denaturation showed that all mutants behaved similarly to the wild type in the free energy of denaturation, suggesting that Tyr-271 and Asn-279 are not critical for the conformational stability of pol beta. (iii) The Kd(app) for the correct dNTP was lower than that for the incorrect dNTP by a factor of 10-30 in the case of wild-type pol beta. Upon mutation to give N279A and N279Q, the Kd(app) for the correct dNTP increased by a factor of 15-25. As a consequence, the Kd(app) values for the correct and incorrect nucleotides were similar for N279A and N279Q, suggesting that the main function of the side chain of Asn-279 is in discrimination between the binding of correct and incorrect dNTPs. (iv) In the case of the Y271A mutant, the fidelity and the catalytic efficiency kpol/Kd(app) were little perturbed relative to the wild type. However, both the kpol and Kd(app) values for dNTP were 4-8 times lower in the case of the Y271A mutant than the corresponding values for wild-type pol beta. Since the chemical step may not be rate-limiting for wild-type pol beta, the effect on kpol could be quite significant if it is caused by a perturbation in the chemical step. (v) Pol beta displayed the greatest specificity towards the G:C base pair, which is incorporated during base excision repair of G:U and G:T mispairs. This specificity was slightly enhanced for the Y271F mutant.
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- Beard W. A., Osheroff W. P., Prasad R., Sawaya M. R., Jaju M., Wood T. G., Kraut J., Kunkel T. A., Wilson S. H. Enzyme-DNA interactions required for efficient nucleotide incorporation and discrimination in human DNA polymerase beta. J Biol Chem. 1996 May 24;271(21):12141–12144. doi: 10.1074/jbc.271.21.12141. [DOI] [PubMed] [Google Scholar]
- Beese L. S., Derbyshire V., Steitz T. A. Structure of DNA polymerase I Klenow fragment bound to duplex DNA. Science. 1993 Apr 16;260(5106):352–355. doi: 10.1126/science.8469987. [DOI] [PubMed] [Google Scholar]
- Berger H., Jr, Huang R. C., Irvin J. L. Purification and characterization of a deoxyribonucleic acid polymerase from rat liver. J Biol Chem. 1971 Dec 10;246(23):7275–7283. [PubMed] [Google Scholar]
- Bryant F. R., Johnson K. A., Benkovic S. J. Elementary steps in the DNA polymerase I reaction pathway. Biochemistry. 1983 Jul 19;22(15):3537–3546. doi: 10.1021/bi00284a001. [DOI] [PubMed] [Google Scholar]
- Carroll S. S., Cowart M., Benkovic S. J. A mutant of DNA polymerase I (Klenow fragment) with reduced fidelity. Biochemistry. 1991 Jan 22;30(3):804–813. doi: 10.1021/bi00217a034. [DOI] [PubMed] [Google Scholar]
- Casas-Finet J. R., Kumar A., Morris G., Wilson S. H., Karpel R. L. Spectroscopic studies of the structural domains of mammalian DNA beta-polymerase. J Biol Chem. 1991 Oct 15;266(29):19618–19625. [PubMed] [Google Scholar]
- Date T., Yamaguchi M., Hirose F., Nishimoto Y., Tanihara K., Matsukage A. Expression of active rat DNA polymerase beta in Escherichia coli. Biochemistry. 1988 Apr 19;27(8):2983–2990. doi: 10.1021/bi00408a048. [DOI] [PubMed] [Google Scholar]
- Davies J. F., 2nd, Almassy R. J., Hostomska Z., Ferre R. A., Hostomsky Z. 2.3 A crystal structure of the catalytic domain of DNA polymerase beta. Cell. 1994 Mar 25;76(6):1123–1133. doi: 10.1016/0092-8674(94)90388-3. [DOI] [PubMed] [Google Scholar]
- Dobashi Y., Shuin T., Tsuruga H., Uemura H., Torigoe S., Kubota Y. DNA polymerase beta gene mutation in human prostate cancer. Cancer Res. 1994 Jun 1;54(11):2827–2829. [PubMed] [Google Scholar]
- Frey M. W., Sowers L. C., Millar D. P., Benkovic S. J. The nucleotide analog 2-aminopurine as a spectroscopic probe of nucleotide incorporation by the Klenow fragment of Escherichia coli polymerase I and bacteriophage T4 DNA polymerase. Biochemistry. 1995 Jul 18;34(28):9185–9192. doi: 10.1021/bi00028a031. [DOI] [PubMed] [Google Scholar]
- Goodman M. F., Creighton S., Bloom L. B., Petruska J. Biochemical basis of DNA replication fidelity. Crit Rev Biochem Mol Biol. 1993;28(2):83–126. doi: 10.3109/10409239309086792. [DOI] [PubMed] [Google Scholar]
- Hunter W. N., Brown T., Anand N. N., Kennard O. Structure of an adenine-cytosine base pair in DNA and its implications for mismatch repair. Nature. 1986 Apr 10;320(6062):552–555. doi: 10.1038/320552a0. [DOI] [PubMed] [Google Scholar]
- Johnson K. A. Conformational coupling in DNA polymerase fidelity. Annu Rev Biochem. 1993;62:685–713. doi: 10.1146/annurev.bi.62.070193.003345. [DOI] [PubMed] [Google Scholar]
- Johnson K. A. Rapid kinetic analysis of mechanochemical adenosinetriphosphatases. Methods Enzymol. 1986;134:677–705. doi: 10.1016/0076-6879(86)34129-6. [DOI] [PubMed] [Google Scholar]
- Kati W. M., Johnson K. A., Jerva L. F., Anderson K. S. Mechanism and fidelity of HIV reverse transcriptase. J Biol Chem. 1992 Dec 25;267(36):25988–25997. [PubMed] [Google Scholar]
- Kohlstaedt L. A., Wang J., Friedman J. M., Rice P. A., Steitz T. A. Crystal structure at 3.5 A resolution of HIV-1 reverse transcriptase complexed with an inhibitor. Science. 1992 Jun 26;256(5065):1783–1790. doi: 10.1126/science.1377403. [DOI] [PubMed] [Google Scholar]
- Kunkel T. A., Alexander P. S. The base substitution fidelity of eucaryotic DNA polymerases. Mispairing frequencies, site preferences, insertion preferences, and base substitution by dislocation. J Biol Chem. 1986 Jan 5;261(1):160–166. [PubMed] [Google Scholar]
- Kunkel T. A. Rapid and efficient site-specific mutagenesis without phenotypic selection. Proc Natl Acad Sci U S A. 1985 Jan;82(2):488–492. doi: 10.1073/pnas.82.2.488. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leavitt M. C., Ito J. T5 DNA polymerase: structural--functional relationships to other DNA polymerases. Proc Natl Acad Sci U S A. 1989 Jun;86(12):4465–4469. doi: 10.1073/pnas.86.12.4465. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lopez P., Martinez S., Diaz A., Espinosa M., Lacks S. A. Characterization of the polA gene of Streptococcus pneumoniae and comparison of the DNA polymerase I it encodes to homologous enzymes from Escherichia coli and phage T7. J Biol Chem. 1989 Mar 5;264(7):4255–4263. [PubMed] [Google Scholar]
- Matsumoto Y., Bogenhagen D. F. Repair of a synthetic abasic site in DNA in a Xenopus laevis oocyte extract. Mol Cell Biol. 1989 Sep;9(9):3750–3757. doi: 10.1128/mcb.9.9.3750. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Matsumoto Y., Kim K. Excision of deoxyribose phosphate residues by DNA polymerase beta during DNA repair. Science. 1995 Aug 4;269(5224):699–702. doi: 10.1126/science.7624801. [DOI] [PubMed] [Google Scholar]
- Ollis D. L., Brick P., Hamlin R., Xuong N. G., Steitz T. A. Structure of large fragment of Escherichia coli DNA polymerase I complexed with dTMP. 1985 Feb 28-Mar 6Nature. 313(6005):762–766. doi: 10.1038/313762a0. [DOI] [PubMed] [Google Scholar]
- Pace C. N. Determination and analysis of urea and guanidine hydrochloride denaturation curves. Methods Enzymol. 1986;131:266–280. doi: 10.1016/0076-6879(86)31045-0. [DOI] [PubMed] [Google Scholar]
- Patel S. S., Wong I., Johnson K. A. Pre-steady-state kinetic analysis of processive DNA replication including complete characterization of an exonuclease-deficient mutant. Biochemistry. 1991 Jan 15;30(2):511–525. doi: 10.1021/bi00216a029. [DOI] [PubMed] [Google Scholar]
- Pelletier H., Sawaya M. R., Kumar A., Wilson S. H., Kraut J. Structures of ternary complexes of rat DNA polymerase beta, a DNA template-primer, and ddCTP. Science. 1994 Jun 24;264(5167):1891–1903. [PubMed] [Google Scholar]
- Piotto M., Saudek V., Sklenár V. Gradient-tailored excitation for single-quantum NMR spectroscopy of aqueous solutions. J Biomol NMR. 1992 Nov;2(6):661–665. doi: 10.1007/BF02192855. [DOI] [PubMed] [Google Scholar]
- Singhal R. K., Prasad R., Wilson S. H. DNA polymerase beta conducts the gap-filling step in uracil-initiated base excision repair in a bovine testis nuclear extract. J Biol Chem. 1995 Jan 13;270(2):949–957. doi: 10.1074/jbc.270.2.949. [DOI] [PubMed] [Google Scholar]
- Singhal R. K., Wilson S. H. Short gap-filling synthesis by DNA polymerase beta is processive. J Biol Chem. 1993 Jul 25;268(21):15906–15911. [PubMed] [Google Scholar]
- Sobol R. W., Horton J. K., Kühn R., Gu H., Singhal R. K., Prasad R., Rajewsky K., Wilson S. H. Requirement of mammalian DNA polymerase-beta in base-excision repair. Nature. 1996 Jan 11;379(6561):183–186. doi: 10.1038/379183a0. [DOI] [PubMed] [Google Scholar]
- Sousa R., Chung Y. J., Rose J. P., Wang B. C. Crystal structure of bacteriophage T7 RNA polymerase at 3.3 A resolution. Nature. 1993 Aug 12;364(6438):593–599. doi: 10.1038/364593a0. [DOI] [PubMed] [Google Scholar]
- Sweasy J. B., Loeb L. A. Mammalian DNA polymerase beta can substitute for DNA polymerase I during DNA replication in Escherichia coli. J Biol Chem. 1992 Jan 25;267(3):1407–1410. [PubMed] [Google Scholar]
- Wang L., Patel U., Ghosh L., Banerjee S. DNA polymerase beta mutations in human colorectal cancer. Cancer Res. 1992 Sep 1;52(17):4824–4827. [PubMed] [Google Scholar]
- Werneburg B. G., Ahn J., Zhong X., Hondal R. J., Kraynov V. S., Tsai M. D. DNA polymerase beta: pre-steady-state kinetic analysis and roles of arginine-283 in catalysis and fidelity. Biochemistry. 1996 Jun 4;35(22):7041–7050. doi: 10.1021/bi9527202. [DOI] [PubMed] [Google Scholar]
- Wiebauer K., Jiricny J. Mismatch-specific thymine DNA glycosylase and DNA polymerase beta mediate the correction of G.T mispairs in nuclear extracts from human cells. Proc Natl Acad Sci U S A. 1990 Aug;87(15):5842–5845. doi: 10.1073/pnas.87.15.5842. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wong I., Patel S. S., Johnson K. A. An induced-fit kinetic mechanism for DNA replication fidelity: direct measurement by single-turnover kinetics. Biochemistry. 1991 Jan 15;30(2):526–537. doi: 10.1021/bi00216a030. [DOI] [PubMed] [Google Scholar]
