Abstract
The Escherichia coli RuvA and RuvB proteins interact specifically with Holliday junctions to promote ATP-dependent branch migration during genetic recombination and DNA repair. In the work described here, glycerol gradient centrifugation was used to investigate the requirements for the formation of pre-branch migration complexes. Since gradient centrifugation provides a simple and gentle method to analyse relatively unstable protein-DNA complexes, we were able to detect RuvA- and RuvAB-Holliday junction complexes without the need for chemical fixation. Using 35S-labelled RuvA protein and 3H-labelled Holliday junctions, we show that RuvA acts as a helicase accessory factor that loads the RuvB helicase onto the Holliday junction by structure-specific interactions. The resulting complex contained both RuvA and RuvB, as detected by Western blotting using serum raised against RuvA and RuvB. The stoichiometry of binding was estimated to be approximately four RuvA tetramers per junction. Formation of the RuvAB-Holliday junction complex required the presence of divalent metal ions and occurred without the need for ATP. However, the stability of the complex was enhanced by the presence of ATP gamma S, a non-hydrolysable ATP analogue. The data support a model for branch migration in which structure-specific binding of Holliday junctions by RuvA targets the assembly of hexameric RuvB rings on DNA. Specific loading of the RuvB ring helicase by RuvA is likely to be the initial step towards ATP-dependent branch migration.
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- Adams D. E., Tsaneva I. R., West S. C. Dissociation of RecA filaments from duplex DNA by the RuvA and RuvB DNA repair proteins. Proc Natl Acad Sci U S A. 1994 Oct 11;91(21):9901–9905. doi: 10.1073/pnas.91.21.9901. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Adams D. E., West S. C. Unwinding of closed circular DNA by the Escherichia coli RuvA and RuvB recombination/repair proteins. J Mol Biol. 1995 Mar 31;247(3):404–417. doi: 10.1006/jmbi.1995.0149. [DOI] [PubMed] [Google Scholar]
- Bennett R. J., Dunderdale H. J., West S. C. Resolution of Holliday junctions by RuvC resolvase: cleavage specificity and DNA distortion. Cell. 1993 Sep 24;74(6):1021–1031. doi: 10.1016/0092-8674(93)90724-5. [DOI] [PubMed] [Google Scholar]
- Bennett R. J., West S. C. RuvC protein resolves Holliday junctions via cleavage of the continuous (noncrossover) strands. Proc Natl Acad Sci U S A. 1995 Jun 6;92(12):5635–5639. doi: 10.1073/pnas.92.12.5635. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Benson F. E., Illing G. T., Sharples G. J., Lloyd R. G. Nucleotide sequencing of the ruv region of Escherichia coli K-12 reveals a LexA regulated operon encoding two genes. Nucleic Acids Res. 1988 Feb 25;16(4):1541–1549. doi: 10.1093/nar/16.4.1541. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Benson F., Collier S., Lloyd R. G. Evidence of abortive recombination in ruv mutants of Escherichia coli K12. Mol Gen Genet. 1991 Feb;225(2):266–272. doi: 10.1007/BF00269858. [DOI] [PubMed] [Google Scholar]
- Connolly B., Parsons C. A., Benson F. E., Dunderdale H. J., Sharples G. J., Lloyd R. G., West S. C. Resolution of Holliday junctions in vitro requires the Escherichia coli ruvC gene product. Proc Natl Acad Sci U S A. 1991 Jul 15;88(14):6063–6067. doi: 10.1073/pnas.88.14.6063. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dunderdale H. J., Benson F. E., Parsons C. A., Sharples G. J., Lloyd R. G., West S. C. Formation and resolution of recombination intermediates by E. coli RecA and RuvC proteins. Nature. 1991 Dec 19;354(6354):506–510. doi: 10.1038/354506a0. [DOI] [PubMed] [Google Scholar]
- Dunderdale H. J., Sharples G. J., Lloyd R. G., West S. C. Cloning, overexpression, purification, and characterization of the Escherichia coli RuvC Holliday junction resolvase. J Biol Chem. 1994 Feb 18;269(7):5187–5194. [PubMed] [Google Scholar]
- Dunderdale H. J., West S. C. Recombination genes and proteins. Curr Opin Genet Dev. 1994 Apr;4(2):221–228. doi: 10.1016/s0959-437x(05)80048-6. [DOI] [PubMed] [Google Scholar]
- Hiom K., West S. C. Branch migration during homologous recombination: assembly of a RuvAB-Holliday junction complex in vitro. Cell. 1995 Mar 10;80(5):787–793. doi: 10.1016/0092-8674(95)90357-7. [DOI] [PubMed] [Google Scholar]
- Iwasaki H., Shiba T., Makino K., Nakata A., Shinagawa H. Overproduction, purification, and ATPase activity of the Escherichia coli RuvB protein involved in DNA repair. J Bacteriol. 1989 Oct;171(10):5276–5280. doi: 10.1128/jb.171.10.5276-5280.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Iwasaki H., Takahagi M., Nakata A., Shinagawa H. Escherichia coli RuvA and RuvB proteins specifically interact with Holliday junctions and promote branch migration. Genes Dev. 1992 Nov;6(11):2214–2220. doi: 10.1101/gad.6.11.2214. [DOI] [PubMed] [Google Scholar]
- Iwasaki H., Takahagi M., Shiba T., Nakata A., Shinagawa H. Escherichia coli RuvC protein is an endonuclease that resolves the Holliday structure. EMBO J. 1991 Dec;10(13):4381–4389. doi: 10.1002/j.1460-2075.1991.tb05016.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mitchell A. H., West S. C. Hexameric rings of Escherichia coli RuvB protein. Cooperative assembly, processivity and ATPase activity. J Mol Biol. 1994 Oct 21;243(2):208–215. doi: 10.1006/jmbi.1994.1648. [DOI] [PubMed] [Google Scholar]
- Müller B., Tsaneva I. R., West S. C. Branch migration of Holliday junctions promoted by the Escherichia coli RuvA and RuvB proteins. I. Comparison of RuvAB- and RuvB-mediated reactions. J Biol Chem. 1993 Aug 15;268(23):17179–17184. [PubMed] [Google Scholar]
- Panyutin I. G., Biswas I., Hsieh P. A pivotal role for the structure of the Holliday junction in DNA branch migration. EMBO J. 1995 Apr 18;14(8):1819–1826. doi: 10.1002/j.1460-2075.1995.tb07170.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Parsons C. A., Stasiak A., Bennett R. J., West S. C. Structure of a multisubunit complex that promotes DNA branch migration. Nature. 1995 Mar 23;374(6520):375–378. doi: 10.1038/374375a0. [DOI] [PubMed] [Google Scholar]
- Parsons C. A., Tsaneva I., Lloyd R. G., West S. C. Interaction of Escherichia coli RuvA and RuvB proteins with synthetic Holliday junctions. Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5452–5456. doi: 10.1073/pnas.89.12.5452. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Parsons C. A., West S. C. Formation of a RuvAB-Holliday junction complex in vitro. J Mol Biol. 1993 Jul 20;232(2):397–405. doi: 10.1006/jmbi.1993.1399. [DOI] [PubMed] [Google Scholar]
- Sharples G. J., Benson F. E., Illing G. T., Lloyd R. G. Molecular and functional analysis of the ruv region of Escherichia coli K-12 reveals three genes involved in DNA repair and recombination. Mol Gen Genet. 1990 Apr;221(2):219–226. doi: 10.1007/BF00261724. [DOI] [PubMed] [Google Scholar]
- Shiba T., Iwasaki H., Nakata A., Shinagawa H. Escherichia coli RuvA and RuvB proteins involved in recombination repair: physical properties and interactions with DNA. Mol Gen Genet. 1993 Mar;237(3):395–399. doi: 10.1007/BF00279443. [DOI] [PubMed] [Google Scholar]
- Shiba T., Iwasaki H., Nakata A., Shinagawa H. SOS-inducible DNA repair proteins, RuvA and RuvB, of Escherichia coli: functional interactions between RuvA and RuvB for ATP hydrolysis and renaturation of the cruciform structure in supercoiled DNA. Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8445–8449. doi: 10.1073/pnas.88.19.8445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shinagawa H., Makino K., Amemura M., Kimura S., Iwasaki H., Nakata A. Structure and regulation of the Escherichia coli ruv operon involved in DNA repair and recombination. J Bacteriol. 1988 Sep;170(9):4322–4329. doi: 10.1128/jb.170.9.4322-4329.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stasiak A., Tsaneva I. R., West S. C., Benson C. J., Yu X., Egelman E. H. The Escherichia coli RuvB branch migration protein forms double hexameric rings around DNA. Proc Natl Acad Sci U S A. 1994 Aug 2;91(16):7618–7622. doi: 10.1073/pnas.91.16.7618. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Takahagi M., Iwasaki H., Shinagawa H. Structural requirements of substrate DNA for binding to and cleavage by RuvC, a Holliday junction resolvase. J Biol Chem. 1994 May 27;269(21):15132–15139. [PubMed] [Google Scholar]
- Tsaneva I. R., Illing G., Lloyd R. G., West S. C. Purification and properties of the RuvA and RuvB proteins of Escherichia coli. Mol Gen Genet. 1992 Oct;235(1):1–10. doi: 10.1007/BF00286175. [DOI] [PubMed] [Google Scholar]
- Tsaneva I. R., Müller B., West S. C. ATP-dependent branch migration of Holliday junctions promoted by the RuvA and RuvB proteins of E. coli. Cell. 1992 Jun 26;69(7):1171–1180. doi: 10.1016/0092-8674(92)90638-s. [DOI] [PubMed] [Google Scholar]
- Tsaneva I. R., Müller B., West S. C. RuvA and RuvB proteins of Escherichia coli exhibit DNA helicase activity in vitro. Proc Natl Acad Sci U S A. 1993 Feb 15;90(4):1315–1319. doi: 10.1073/pnas.90.4.1315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- West S. C. Enzymes and molecular mechanisms of genetic recombination. Annu Rev Biochem. 1992;61:603–640. doi: 10.1146/annurev.bi.61.070192.003131. [DOI] [PubMed] [Google Scholar]


