News & Views

  • Lethal weapon: bacteria’s high-risk suicide strategy   
    Caption: The ‘suicide complex’ ToxIN. Credit: Francesca Short.

Lethal weapon: bacteria’s high-risk suicide strategy  

Jan 14 2013 Read 885 Times

Research has shown that some bacterial cells carry a molecular ‘suicide complex’ to kill themselves in the event of lethal infection by viral parasites. Such ‘altruistic suicide’ prevents or limits viral replication and protects the rest of the bacterial population from subsequent infection. In the longer term, the discovery could be exploited to enable the development of new small molecule antibacterial drugs.


Bacteria accomplish this through a high-risk strategy in which their lethal weapon is kept to hand at all times, but is neutralised until viral infection of the bacterial cell triggers its release from inhibition.
The mechanism was discovered in the bacterial plant pathogen by researchers led by Professors George Salmond and Ben Luisi in the University of Cambridge’s Department of Biochemistry. Their work, reported in the journal Proceedings of the National Academy of Science (Dec) shows that a suicide complex, ToxIN, is not induced but exists all the time in the bacterial cell; to avoid killing the bacterial cell, it is held in a suppressed, inert form until viral infection triggers the release of a protein toxin (ToxN) from an RNA antitoxin (ToxI) partner. The toxin then causes the death of both the bacterium and the infecting virus.

The success of the antiviral system therefore depends heavily on maintaining a very strong inhibition or suppression of the toxin by its RNA antitoxin, to ensure that the host cell is not damaged in the absence of invading viruses or other stresses. Small RNAs have multiple essential roles in bacteria, but examples of naturally occurring RNA molecules that act as direct protein inhibitors are rare.

Professor George Salmond, deputy head at the Department of Biochemistry, said: “The results present a picture of ToxIN as an addictive, self-assembling – and potentially lethal – molecular machine, which can drive remarkable adaptive advantages in populations of bacterial hosts, including those under threat from lethal viral predation.”

The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), explores the powerful ToxN-inhibiting activity of the ToxI RNA. It shows that the ToxI RNA ‘neutralises’ its toxin partner through the self-assembly of a triangular ToxI-ToxN macromolecular complex, previously observed by earlier BBSRC-funded crystallographic studies published in Nature Structural and Molecular Biology in 2011.

Reader comments

Do you like or dislike what you have read? Why not post a comment to tell others / the manufacturer and our Editor what you think. To leave comments please complete the form below. Providing the content is approved, your comment will be on screen in less than 24 hours. Leaving comments on product information and articles can assist with future editorial and article content. Post questions, thoughts or simply whether you like the content.

Post a Comment




Digital Edition

Lab Asia August 2019

August 2019

In this Issue Articles Mass Spectrometry & Spectroscopy 67th ASMS Conference on Mass Spectrometry and Allied Topics Chromatography Using Gas Chromatography for measuring atmo...

View all digital editions

Events

DioXin 2019

Aug 25 2019 Kyoto, Japan

ACS National Meeting & Expo, Fall 2019

Aug 25 2019 San Diego, CA, USA

Microscopy Conference 2019

Sep 01 2019 Berlin, Germany

BMSS Annual Meeting

Sep 03 2019 Manchester, UK

JASIS 2019

Sep 04 2019 Chiba City, Japan

View all events