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The acidic pin of RuvA modulates Holliday junction binding and processing by the RuvABC resolvasome.

Ingleston, S.M.; Sharples, G.J.; Lloyd, R.G.

Authors

S.M. Ingleston

R.G. Lloyd



Abstract

Holliday junctions are four-way branched DNA structures formed during recombination, replication and repair. They are processed in Escherichia coli by the RuvA, RuvB and RuvC proteins. RuvA targets the junction and facilitates loading of RuvB helicase and RuvC endonuclease to form complexes that catalyse junction branch migration (RuvAB) and resolution (RuvABC). We investigated the role of RuvA in these reactions and in particular the part played by the acidic pin located on its DNA-binding surface. By making appropriate substitutions of two key amino acids (Glu55 and Asp56), we altered the charge on the pin and investigated how this affected junction binding and processing. We show that two negative charges on each subunit of the pin are crucial. They facilitate junction targeting by preventing binding to duplex DNA and also constrain branch migration by RuvAB in a manner critical for junction processing. These findings provide the first direct evidence that RuvA has a mechanistic role in branch migration. They also provide insight into the coupling of branch migration and resolution by the RuvABC resolvasome.

Citation

Ingleston, S., Sharples, G., & Lloyd, R. (2000). The acidic pin of RuvA modulates Holliday junction binding and processing by the RuvABC resolvasome. The EMBO Journal, 19, 6266-6274

Journal Article Type Article
Publication Date 2000
Journal EMBO Journal
Print ISSN 0261-4189
Publisher EMBO Press
Volume 19
Pages 6266-6274
Publisher URL http://www.ncbi.nlm.nih.gov/cgi-bin/Entrez/referer?http://www.emboj.org/cgi/content/abstract/19/22/6266