Maintaining the ribosomal reading frame: the influence of the E site during translational regulation of release factor 2.
Maintenance of the translation reading frame is one of the most remarkable achievements of the ribosome while decoding the information of an mRNA. Loss of the reading frame through spontaneous frameshifting occurs with a frequency of one in 30,000 amino acid incorporations. However, at many recoding sites, the mechanism that controls reading frame maintenance is switched off. One such example is the programmed +1 frameshift site of the prfB gene encoding the termination factor RF2, in which slippage into the forward frame by one nucleotide can attain an efficiency of approximately 100%, namely, four orders of magnitude higher than normally observed. Here, using the RF2 frameshift window, we demonstrate that premature release of the E site tRNA from the ribosome is coupled with high-level frameshifting. Consistently, in a minimal system, the presence of the E site tRNA prevents the +1 frameshift event, illustrating the importance of the E site for reading-frame maintenance.
Márquez
Viter
V
Max-Planck-Institut für Molekulare Genetik, AG Ribosomen, Ihnestrasse 73, D-14195 Berlin, Germany.
Wilson
Daniel N
DN
Tate
Warren P
WP
Triana-Alonso
Francisco
F
Nierhaus
Knud H
KH
D000595:Amino Acid Sequence; D000926:Anticodon / Q000378:metabolism; D001483:Base Sequence; D003062:Codon / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D016368:Frameshift Mutation; D018965:Frameshifting, Ribosomal; D007700:Kinetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors / Q000235:genetics*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry / Q000378:metabolism; D012364:RNA, Transfer, Trp / Q000378:metabolism; D016364:Reading Frames / Q000235:genetics*; D012270:Ribosomes / Q000235:genetics* / Q000378:metabolism
D000926:Anticodon; D003062:Codon; D010454:Peptide Termination Factors; D012333:RNA, Messenger; D012364:RNA, Transfer, Trp