| Literature DB >> 19540850 |
Debora Lucarelli1, Ying A Wang, Vitold E Galkin, Xiong Yu, Dale B Wigley, Edward H Egelman.
Abstract
The E. coli RecBCD enzyme facilitates the loading of RecA onto single-stranded DNA produced by the combined helicase/nuclease activity of RecBCD. The nuclease domain of RecB protein, RecB(nuc), has been previously shown to bind RecA. Surprisingly, RecB(nuc) also binds to phage and eukaryotic homologs of RecA, leading to the suggestion that RecB(nuc) interacts with the polymerization motif that is present in all three proteins. This mode of interaction could only be with monomeric RecA, as this motif would be buried in filaments. We show that RecB(nuc) binds extensively to the outside of RecA-DNA filaments. Three-dimensional reconstructions suggest that RecB(nuc) binds to the ATP-binding core of RecA, with a displacement of the C-terminal domain of RecA. Solution experiments confirm that the interaction of RecB(nuc) is only with the RecA core. Since the RecA C-terminal domain has been shown to be regulatory, the interaction observed may be part of the loading mechanism where RecB displaces the RecA C-terminal domain and activates a RecA monomer for polymerization.Entities:
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Year: 2009 PMID： 19540850 PMCID： PMC2749006 DOI： 10.1016/j.jmb.2009.06.042
Source DB: PubMed Journal: J Mol Biol ISSN： 0022-2836 Impact factor: 5.469