Fig. 4.

Conformational differences between the two classes of the 80S•TSV IRES complex (structure I and structure II). Rotation of the small 40S subunit in structure II (gray) relative to that in structure I (teal) is coupled with rotation of the IRES (gray surface in structure II and red surface in structure I) and the L1 stalk of the large subunit (gray ribbon in structure II and yellow ribbon in structure I). The superposition was obtained by structural alignment of the 25S rRNA from the 80S•TSV IRES structure corresponding to structure I on that for structure II. The 40S subunit proteins are not shown for the sake of clarity.