Data collection and refinement statistics.

aAU: asymmetric unit of the crystal.
bNumbers in parenthesis correspond to the outer resolution bin.
cA measure of agreement among multiple measurements of the same reflections. Rmerge is calculated as follows: Ii(hkl) is the intensity of an individual measurement of the reflection with Miller indices hkl, and I(hkl) is the intensity from multiple observations:Rmerge = ∑hkl∑i|Ii(hkl)−I(hkl)|/∑hkl∑i|Ii(hkl)|.
dR(work) = ∑hkl| Fobs−Fcalc |/∑hkl|Fobs|, where Fobs and Fcalc are the observed and calculated structure factor amplitudes, respectively. The free R-factor, R(free), is computed in the same manner as R(work), but using only a small set (5%) of randomly chosen reflections not used in the refinement of the model.
eThe Ramachandran plot was calculated using PHENIX.