Figure 3. Contact between the downstream region of mRNA with the head of the 30S subunit.
(A) The entry to the downstream mRNA entry tunnel is surrounded by proteins uS3, uS4, and uS5. Positions +14 to +21 contact a positively charged patch on the surface of protein uS3 in the 30S head (Fig. S17). (B) Path of the downstream mRNA and (C) 90° rotated view. (D) Docking on the 30S body of the classical structure (17) (gray) shows that rotation of the head in the ap/ap intermediate structure translocates the mRNA by one codon. A-codon (yellow) and P-codon (red).