X-ray data collection and refinement statistics.

All data sets were collected from a single crystal.aBL-13B1/13C1 National Synchrotron Radiation Research Center (NSRRC), HsinChu, Taiwan; Taiwan BL-12B2 beamline at SPring-8, Hyogo, Japan.bValues in parentheses refer to statistics in the highest-resolution shell.cRmerge = ∑|Iobs−I>|∑Iobs.dR = ∑|Fobs−Fcalc|/∑Fobs, where Fobs and Fcalc are the observed and calculated structure factor amplitudes, respectively.eRfree was computed using 5% of the data assigned randomly.fr.m.s., root mean square.