Table 1. X-ray data and refinement statistics.

Data set
Space group Unit cell Resolution (Å) Measured reflections Unique reflections Redundancy Completeness (%, highest shell) Mean I/σI (highest shell) Rsym (%, highest shell)	P6522 a = 100.5 Å, c = 138.3 Å 2.7 167,791 11,805 14.2 99.3 (99.5) 44.1 (1.6) 10.7 (100)
Refinement
Resolution (Å) Number of reflections |F| > 0 σF R-factor/R-free (%) Number of protein atoms Number of GTP molecules Number of water molecules rmsd bond lengths (Å) rmsd bond angles (°)	2.7 10,593 21.1/25.3 2203 1 0 0.008 0.97