Lamotrigine compromises the fidelity of initiator tRNA recruitment to the ribosomal P-site by IF2 and the RbfA release from 30S ribosomes in Escherichia coli

Singh, S and Lahry, K and Mandava, CS and Singh, J and Shah, RA and Sanyal, S and Varshney, U (2023) Lamotrigine compromises the fidelity of initiator tRNA recruitment to the ribosomal P-site by IF2 and the RbfA release from 30S ribosomes in Escherichia coli. In: RNA Biology, 20 (1). pp. 681-692.

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Abstract

Lamotrigine (Ltg), an anticonvulsant drug, targets initiation factor 2 (IF2), compromises ribosome biogenesis and causes toxicity to Escherichia coli. However, our understanding of Ltg toxicity in E. coli remains unclear. While our in vitro assays reveal no effects of Ltg on the ribosome-dependent GTPase activity of IF2 or its role in initiation as measured by dipeptide formation in a fast kinetics assay, the in vivo experiments show that Ltg causes accumulation of the 17S precursor of 16S rRNA and leads to a decrease in polysome levels in E. coli. IF2 overexpression in E. coli increases Ltg toxicity. However, the overexpression of initiator tRNA (i-tRNA) protects it from the Ltg toxicity. The depletion of i-tRNA or overexpression of its 3GC mutant (lacking the characteristic 3GC base pairs in anticodon stem) enhances Ltg toxicity, and this enhancement in toxicity is synthetic with IF2 overexpression. The Ltg treatment itself causes a detectable increase in IF2 levels in E. coli and allows initiation with an elongator tRNA, suggesting compromise in the fidelity/specificity of IF2 function. Also, Ltg causes increased accumulation of ribosome-binding factor A (RbfA) on 30S ribosomal subunit. Based on our genetic and biochemical investigations, we show that Ltg compromises the function of i-tRNA/IF2 complex in ribosome maturation. © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

Item Type:	Journal Article
Publication:	RNA Biology
Publisher:	Taylor and Francis Ltd.
Additional Information:	The copyright for this article belongs to the Taylor and Francis Ltd.
Keywords:	anticonvulsive agent; Escherichia coli protein; initiation factor 2; lamotrigine; methionine transfer RNA; RbfA protein, E coli; ribosome protein; RNA 16S, Escherichia coli; genetics; ribosome, Anticonvulsants; Escherichia coli; Escherichia coli Proteins; Lamotrigine; Prokaryotic Initiation Factor-2; Ribosomal Proteins; Ribosomes; RNA, Ribosomal, 16S; RNA, Transfer, Met
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	28 Oct 2023 08:17
Last Modified:	28 Oct 2023 08:17
URI:	https://eprints.iisc.ac.in/id/eprint/83152

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