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Impact of rRNA methylations on ribosome recycling and fidelity of initiation in Escherichia coli
Author(s) -
Seshadri Anuradha,
Dubey Badrinath,
Weber Michael H. W.,
Varshney Umesh
Publication year - 2009
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2009.06685.x
Subject(s) - ribosome , transfer rna , ribosomal rna , biology , 50s , ribosomal protein , rna , p site , eukaryotic ribosome , translation (biology) , 5.8s ribosomal rna , genetics , 23s ribosomal rna , a site , protein biosynthesis , computational biology , microbiology and biotechnology , binding site , messenger rna , gene
Summary Ribosomal RNA (rRNA) contains a number of modified nucleosides in functionally important regions including the intersubunit bridge regions. As the activity of ribosome recycling factor (RRF) in separating the large and the small subunits of the ribosome involves disruption of intersubunit bridges, we investigated the impact of rRNA methylations on ribosome recycling. We show that deficiency of rRNA methylations, especially at positions 1518 and 1519 of 16S rRNA near the interface with the 50S subunit and in the vicinity of the IF3 binding site, adversely affects the efficiency of RRF‐mediated ribosome recycling. In addition, we show that a compromise in the RRF activity affords increased initiation with a mutant tRNA fMet wherein the three consecutive G‐C base pairs ( 29 GGG 31 : 39 CCC 41 ), a highly conserved feature of the initiator tRNAs, were mutated to those found in the elongator tRNA Met ( 29 UCA 31 : 39 ψGA 41 ). This observation has allowed us to uncover a new role of RRF as a factor that contributes to fidelity of initiator tRNA selection on the ribosome. We discuss these and earlier findings to propose that RRF plays a crucial role during all the steps of protein synthesis.