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. Author manuscript; available in PMC: 2015 Nov 15.
Published in final edited form as: Exp Cell Res. 2014 Jul 9;329(1):139–147. doi: 10.1016/j.yexcr.2014.07.007

Figure 3.

Figure 3

ATP induced conformational changes in the catalytic head of MRN complex. The globular domain comprised of Rad50 ATPase and Mre11 nuclease domains is depicted as revealed from crystal structures (Lammens et al., 2011; Lim et al., 2011; Mockel et al., 2011). Mre11 binds Rad50 at the base of coiled coils. In the ATP unbound form, the structure is “open”, with Mre11 nuclease active sites accessible. ATP binding sites are shown as stars. In this state, the complex can engage DNA in a non-end specific manner (Deshpande et al., 2014). Binding of ATP brings the ATPase domains together forming a “closed” state. This form promotes end specific DNA binding and DNA tethering by MR/MRN complex and ATM checkpoint activation (Lee et al., 2013). Although this form blocks the nuclease site, ATP hydrolysis followed by separation of the ATPase domains is required for nuclease activity of Mre11, likely through a transient intermediate, although the structure of this theoretical conformation is unknown.