Crucial contribution of the multiple copies of the initiator tRNA genes in the fidelity of tRNA(fMet) selection on the ribosomal P-site in Escherichia coli

Kapoor, Suman and Das, Gautam and Varshney, Umesh (2011) Crucial contribution of the multiple copies of the initiator tRNA genes in the fidelity of tRNA(fMet) selection on the ribosomal P-site in Escherichia coli. In: Nucleic Acids Research, 39 (1). pp. 202-212.

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Abstract

The accuracy of the initiator tRNA (tRNA(fMet)) selection in the ribosomal P-site is central to the fidelity of protein synthesis. A highly conserved occurrence of three consecutive G-C base pairs in the anticodon stem of tRNA(fMet) contributes to its preferential selection in the P-site. In a genetic screen, using a plasmid borne copy of an inactive tRNA(fMet) mutant wherein the three G-C base pairs were changed, we isolated Escherichia coli strains that allow efficient initiation with the tRNA(fMet) mutant. Here, extensive characterization of two such strains revealed novel mutations in the metZWV promoter severely compromising tRNA(fMet) levels. Low cellular abundance of the chromosomally encoded tRNA(fMet) allows efficient initiation with the tRNA(fMet) mutant and an elongator tRNA(Gln), revealing that a high abundance of the cellular tRNA(fMet) is crucial for the fidelity of initiator tRNA selection on the ribosomal P-site in E. coli. We discuss possible implications of the changes in the cellular tRNA(fMet) abundance in proteome remodeling.

Item Type:	Journal Article
Publication:	Nucleic Acids Research
Publisher:	Oxford University Press
Additional Information:	Copyright of this article belongs to Oxford University Press.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	22 Feb 2011 07:01
Last Modified:	22 Feb 2011 07:01
URI:	http://eprints.iisc.ac.in/id/eprint/35674

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