Abstract
Two nucleases that catalyze the excision of photoproducts from UV-irradiated DNA have been extensively purified from M. luteus (M. lysodeikticus). The first enzyme, an endonuclease, has been purified 5000-fold and is free of conflicting nuclease activities. It introduces single-strand breaks into irradiated DNA but does not act on native or single-stranded DNA. The purified enzyme is activated but not dependent on Mg++ and has an approximate molecular weight of 15,000. Photoproduct excision is absolutely dependent on the second enzyme, a magnesium requiring exonuclease. This enzyme, which has been purified 1000-fold, is devoid of conflicting nucleases. It hydrolyzes irradiated and unirradiated denatured DNA at the same rate, but has no activity on RNA. It only acts on double-stranded DNA which has been both irradiated and pretreated with the endonuclease. The combined action of the endo- and exonuclease results in the quantitative removal of photoproduct regions from UV-irradiated DNA. Approximately five nucleotides are released for every single-strand incision.
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- BOYCE R. P., HOWARD-FLANDERS P. RELEASE OF ULTRAVIOLET LIGHT-INDUCED THYMINE DIMERS FROM DNA IN E. COLI K-12. Proc Natl Acad Sci U S A. 1964 Feb;51:293–300. doi: 10.1073/pnas.51.2.293. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LEHMAN I. R., ROUSSOS G. G., PRATT E. A. The deoxyribonucleases of Escherichia coli. II. Purification and properties of a ribonucleic acid-inhibitable endonuclease. J Biol Chem. 1962 Mar;237:819–828. [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Litman R. M. A deoxyribonucleic acid polymerase from Micrococcus luteus (Micrococcus lysodeikticus) isolated on deoxyribonucleic acid-cellulose. J Biol Chem. 1968 Dec 10;243(23):6222–6233. [PubMed] [Google Scholar]
- Nakayama H., Okubo S., Sekiguchi M., Takagi Y. A deoxyribonuclease activity specific for ultraviolet-irradiated DNA: a chromatographic analysis. Biochem Biophys Res Commun. 1967 Apr 20;27(2):217–223. doi: 10.1016/s0006-291x(67)80064-0. [DOI] [PubMed] [Google Scholar]
- Okubo S., Nakayama H., Sekiguchi M., Takagi Y. A mutant of Micrococcus lyosodeikticus defective in a deoxyribonuclease activity specific for ultraviolet-irradiated DNA. Biochem Biophys Res Commun. 1967 Apr 20;27(2):224–229. doi: 10.1016/s0006-291x(67)80065-2. [DOI] [PubMed] [Google Scholar]
- Pearson M., Johns H. E. Suppression of hydrate and dimer formation in ultraviolet-irradiated poly (A plus U) relative to poly U. J Mol Biol. 1966 Sep;20(2):215–229. doi: 10.1016/0022-2836(66)90061-1. [DOI] [PubMed] [Google Scholar]
- RUPERT C. S. Photoreactivation of transforming DNA by an enzyme from bakers' yeast. J Gen Physiol. 1960 Jan;43:573–595. doi: 10.1085/jgp.43.3.573. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SETLOW R. B., CARRIER W. L. THE DISAPPEARANCE OF THYMINE DIMERS FROM DNA: AN ERROR-CORRECTING MECHANISM. Proc Natl Acad Sci U S A. 1964 Feb;51:226–231. doi: 10.1073/pnas.51.2.226. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SETLOW R. B., SETLOW J. K. Evidence that ultraviolet-induced thymine dimers in DNA cause biological damage. Proc Natl Acad Sci U S A. 1962 Jul 15;48:1250–1257. doi: 10.1073/pnas.48.7.1250. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WULFF D. L., RUPERT C. S. Disappearance of thymine photodimer in ultraviolet irradiated DNA upon treatment with a photoreactivating enzyme from baker's yeast. Biochem Biophys Res Commun. 1962 Apr 20;7:237–240. doi: 10.1016/0006-291x(62)90181-x. [DOI] [PubMed] [Google Scholar]