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Article
Identification of a Key Amino Acid of LuxS Involved in AI-2 Production in Campylobacter jejuni
PLoS One
  • Paul J. Plummer, Iowa State University
  • Jinge Zhu, Ohio State University
  • Masato Akiba, Iowa State University
  • Dehua Pei, Ohio State University
  • Qijing Zhang, Iowa State University
Document Type
Article
Publication Version
Published Version
Publication Date
1-1-2011
DOI
10.1371/journal.pone.0015876
Abstract
Autoinducer-2 (AI-2) mediated quorum sensing has been associated with the expression of virulence factors in a number of pathogenic organisms and has been demonstrated to play a role in motility and cytolethal distending toxin (cdt) production in Campylobacter jejuni. We have initiated the work to determine the molecular basis of AI-2 synthesis and the biological functions of quorum sensing in C. jejuni. In this work, two naturally occurring variants of C. jejuni 81116 were identified, one producing high-levels of AI-2 while the other is defective in AI-2 synthesis. Sequence analysis revealed a G92D mutation in the luxS gene of the defective variant. Complementation of the AI-2− variant with a plasmid encoded copy of the wild-typeluxS gene or reversion of the G92D mutation by site-directed mutagenesis fully restored AI-2 production by the variant. These results indicate that the G92D mutation alone is responsible for the loss of AI-2 activity in C. jejuni. Kinetic analyses showed that the G92D LuxS has a ∼100-fold reduced catalytic activity relative to the wild-type enzyme. Findings from this study identify a previously undescribed amino acid that is essential for AI-2 production by LuxS and provide a unique isogenic pair of naturally occurring variants for us to dissect the functions of AI-2 mediated quorum sensing in Campylobacter.
Comments

This article is from PLoS One 6 (2011): e15876, doi:10.1371/journal.pone.0015876. Posted with permission.

Rights
This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Copyright Owner
Paul J. Plummer, et al
Language
en
File Format
application/pdf
Citation Information
Paul J. Plummer, Jinge Zhu, Masato Akiba, Dehua Pei, et al.. "Identification of a Key Amino Acid of LuxS Involved in AI-2 Production in Campylobacter jejuni" PLoS One Vol. 61 Iss. 1 (2011) p. e15876
Available at: http://works.bepress.com/qijing-zhang/11/