Table 1.

30S head and body rotations

Ribosome state†	30S head rotation	30S body rotation‡	No. of structures	tRNA states
Classical (Cla)	2.0 ± 1.0	−0.8 ± 0.8	8	Classical
P/E Hybrid (Hyb)	5.9 ± 0.7	7.6 ± 1.1	4	P/E Hybrid
Vacant 1 (Vac1)	8.1 ± 0.1	−3.3 ± 0.1	5	No tRNA
Vacant 2 (Vac2)	11.5 ± 1.3	4.9 ± 1.9	4	No tRNA
Vacant 3 (Vac3)	16.3 ± 0.1	−2.4 ± 0.1	4	No tRNA
Chimeric hybrid (Chi)	19.2 ± 1.3	1.8 ± 0.9	4	Chimeric pe/E–hybrid

The magnitudes of 30S head and body rotation for each ribosome complex were determined by the E–R method relative to 2J00 and 2J01 (10) reference structures (Methods). See Table S1 for the complete list of structures used.

^†Defined by the tRNA-binding state. Groups were assigned based on the magnitudes of head rotation and conformational states of bound tRNAs (Methods).

^‡Intersubunit rotation.