Novel Toxin-antitoxin System Xn-mazEF from Xenorhabdus nematophila: Identification, Characterization and Functional Exploration

Author(s): Jogendra Singh Nim, Mohit Yadav, Lalit Kumar Gautam, Chaitali Ghosh, Shakti Sahi, Jitendra Singh Rathore*

Journal Name: Current Computer-Aided Drug Design

Volume 17 , Issue 3 , 2021

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Graphical Abstract:


Background: Xenorhabdus nematophila maintains species-specific mutual interaction with nematodes of Steinernema genus. Type II Toxin Antitoxin (TA) systems, the mazEF TA system controls stress and programmed cell death in bacteria.

Objective: This study elucidates the functional characterization of Xn-mazEF, a mazEF homolog in X. nematophila by computational and in vitro approaches.

Methods: 3D- structural models for Xn-MazE toxin and Xn-MazF antitoxin were generated, validated and characterized for protein - RNA interaction analysis. Further biological and cellular functions of Xn-MazF toxin were also predicted. Molecular dynamics simulations of 50ns for Xn- MazF toxin complexed with nucleic acid units (DU, RU, RC, and RU) were performed. The MazF toxin and complete MazEF operon were endogenously expressed and monitored for the killing of Escherichia coli host cells under arabinose induced tightly regulated system.

Results: Upon induction, E. coli expressing toxin showed rapid killing within four hours and attained up to 65% growth inhibition, while the expression of the entire operon did not show significant killing. The observation suggests that the Xn-mazEF TA system control transcriptional regulation in X. nematophila and helps to manage stress or cause toxicity leading to programmed death of cells.

Conclusion: The study provides insights into structural and functional features of novel toxin, Xn- MazF and provides an initial inference on control of X. nematophila growth regulated by TA systems.

Keywords: maze, mazF, toxin-antitoxin system, endogenous toxicity assay, Xenorhabdus nematophila, molecular dynamics simulation, nucleic acid.

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Article Details

Year: 2021
Published on: 25 June, 2020
Page: [402 - 411]
Pages: 10
DOI: 10.2174/1573409916666200625135850
Price: $65

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