The effect of aminoacyl‐ or peptidyl‐tRNA at the A‐site on the arrangement of deacylated tRNA at the ribosomal P‐site

摘要

>Photoreactive derivatives of E. coli tRNAPhe bearing arylazido groups on guanine residues (azido-tRNA) were used for affinity labelling of E. coli ribosomes in the region of the P-site when the A-site was either free or occupied by aminoacyl- or peptidyl-tRNA. Corresponding complexes of azido-tRNA with ribosomes and poly(U) were obtained both nonenzymatically and with the use of elongation factors. UV-irradiation of the complexes resulted in labelling of ribosomal proteins (preferentially of 30 S subunit). Proteins S9 and S21 were labelled only when the A-site was free; S14 — only when it was occupied; S11, S13, S19 — in both cases; S5, S7, S12, S20 — in some states.