Features of 80S mammalian ribosome and its subunits.
It is generally believed that basic features of ribosomal functions are universally valid, but a systematic test still stands out for higher eukaryotic 80S ribosomes. Here we report: (i) differences in tRNA and mRNA binding capabilities of eukaryotic and bacterial ribosomes and their subunits. Eukaryotic 40S subunits bind mRNA exclusively in the presence of cognate tRNA, whereas bacterial 30S do bind mRNA already in the absence of tRNA. 80S ribosomes bind mRNA efficiently in the absence of tRNA. In contrast, bacterial 70S interact with mRNA more productively in the presence rather than in the absence of tRNA. (ii) States of initiation (P(i)), pre-translocation (PRE) and post-translocation (POST) of the ribosome were checked and no significant functional differences to the prokaryotic counterpart were observed including the reciprocal linkage between A and E sites. (iii) Eukaryotic ribosomes bind tetracycline with an affinity 15 times lower than that of bacterial ribosomes (K(d) 30 microM and 1-2 microM, respectively). The drug does not effect enzymatic A-site occupation of 80S ribosomes in contrast to non-enzymatic tRNA binding to the A-site. Both observations explain the relative resistance of eukaryotic ribosomes to this antibiotic.
Budkevich
Tatyana V
TV
Max-Planck-Institut für Molekulare Genetik, Ihnestr. 73, D-14195 Berlin, Germany.
El'skaya
Anna V
AV
Nierhaus
Knud H
KH
D000494:Allosteric Regulation; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001419:Bacteria / Q000235:genetics; D010442:Peptide Chain Initiation, Translational; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D011817:Rabbits; D054683:Ribosome Subunits, Large, Eukaryotic / Q000378:metabolism; D054680:Ribosome Subunits, Small, Bacterial / Q000378:metabolism; D054682:Ribosome Subunits, Small, Eukaryotic / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D013752:Tetracycline / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D012333:RNA, Messenger; D012343:RNA, Transfer; D013752:Tetracycline