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. Author manuscript; available in PMC: 2015 Oct 23.
Published in final edited form as: J Mol Biol. 2014 Jul 27;426(21):3479–3499. doi: 10.1016/j.jmb.2014.07.017

Fig. 1.

Fig. 1

Structure of RecBCD enzyme bound to DNA and a “signal transduction” model for the Chi-dependent alteration of RecBCD enzyme. (a) The crystal structure of RecBCD bound to hairpin-shaped DNA (PDB entry 1W36) [18]. The RecB polypeptide is orange, RecC is blue, and RecD is green. In this structure, the 3′-ended strand would encounter the RecB nuclease domain upon exiting the RecC tunnel, in which Chi is likely recognized. (b) A “signal transduction” model for the Chi-dependent change of RecBCD [17]. When Chi is in the RecC tunnel (yellow disk), it prompts RecC to signal RecD to stop unwinding, which in turn signals RecB to nick the 3′-ended strand of DNA near Chi and to begin loading RecA.