The fate of the initiator tRNAs is sensitive to the critical balance between interacting proteins

Thanedar, Swapna and Kumar, Vinay N and Varshney, Umesh (2000) The fate of the initiator tRNAs is sensitive to the critical balance between interacting proteins. In: Journal of Biological Chemistry, 275 (27). pp. 20361-20367.

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Abstract

Formylation of the initiator tRNA is essential for normal growth of Escherichia coil, The initiator tRNA containing the U35A36 mutation (CUA anticodon) initiates from UAG codon, However, an additional mutation at position 72 (72A --> G) renders the tRNA (G72/U35A36) inactive in initiation because it is defective in formylation, In this study, we isolated U1G72/U35A36 tRNA containing a wobble base pair at 1-72 positions as an intragenic suppressor of the G72 mutation. The U1G72/U35A36 tRNA is formylated and participates in initiation. More importantly, we show that the mismatch at 1-72 positions of the initiator tRNA, which was thus far thought to be the hallmark of the resistance of this tRNA against peptidyl-tRNA hydrolase (PTH), is not sufficient, The amino acid attached to the initiator tRNA is also important in conferring protection against PTH. Further, we show that the relative levels of PTH and IF2 influence the path adopted by the initiator tRNAs in protein synthesis. These findings provide an important clue to understand the dual function of the single tRNA(Met) in initiation and elongation, in the mitochondria of various organisms.

Item Type:	Journal Article
Publication:	Journal of Biological Chemistry
Publisher:	The American Society for Biochemistry and Molecular Biology
Additional Information:	Copyright of this article belongs to The American Society for Biochemistry and Molecular Biology.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	09 Aug 2010 06:20
Last Modified:	19 Sep 2010 06:13
URI:	http://eprints.iisc.ac.in/id/eprint/31161

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