Table 3. Geometries for region of switch I and II and P-loop.

Distances d1 (between Cα of His⁸⁷ and the Pγ atom of GTP), d2 (between Cα atoms of His⁸⁷ and Thr⁶⁴), d3 (between Cα atoms of His⁸⁷ and Asp²²), and d4 (between Cα atoms of Thr⁶⁴ and Asp²²) were obtained by averaging these distances from four x-ray structures (4JUW, 4KIY, 4KBT, 4KCY). For EF-Tu, the x-ray structure 4QDS was used. The x-ray POST used PDB 2WRI. “rt” and “nrt” denote rotated and nonrotated structures, respectively (see also Fig. 3).

Distances (Å)	X-ray EF-G average	X-ray EF-Tu	rt	nrt	X-ray POST
d1	7.0	6.6	7.3	7.3	9.0 ( to Pβ)
d2	9.1	9.2	8.8	9.1	19.0
d3	8.8	9.2	10.3	11.3	6.7
d4	10.2	9.5	10.4	11.7	18.5