Assembly of the Escherichia coli RuvABC resolvasome directs the orientation of Holliday junction resolution
AUTOR(ES)
van Gool, Alain J.
FONTE
Cold Spring Harbor Laboratory Press
RESUMO
Genetic recombination can lead to the formation of intermediates in which DNA molecules are linked by Holliday junctions. Movement of a junction along DNA, by a process known as branch migration, leads to heteroduplex formation, whereas resolution of a junction completes the recombination process. Holliday junctions can be resolved in either of two ways, yielding products in which there has, or has not, been an exchange of flanking markers. The ratio of these products is thought to be determined by the frequency with which the two isomeric forms (conformers) of the Holliday junction are cleaved. Recent studies with enzymes that process Holliday junctions in Escherichia coli, the RuvABC proteins, however, indicate that protein binding causes the junction to adopt an open square-planar configuration. Within such a structure, DNA isomerization can have little role in determining the orientation of resolution. To determine the role that junction-specific protein assembly has in determining resolution bias, a defined in vitro system was developed in which we were able to direct the assembly of the RuvABC resolvasome. We found that the bias toward resolution in one orientation or the other was determined simply by the way in which the Ruv proteins were positioned on the junction. Additionally, we provide evidence that supports current models on RuvABC action in which Holliday junction resolution occurs as the resolvasome promotes branch migration.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=316879Documentos Relacionados
- The acidic pin of RuvA modulates Holliday junction binding and processing by the RuvABC resolvasome
- The RuvABC proteins and Holliday junction processing in Escherichia coli.
- Holliday Junction Processing in Bacteria: Insights from the Evolutionary Conservation of RuvABC, RecG, and RusA
- The RuvABC Resolvase Is Indispensable for Recombinational Repair in sbcB15 Mutants of Escherichia coli
- Resolution of Holliday junctions in vitro requires the Escherichia coli ruvC gene product.