This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cavard, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cavard, D.

 Previous Article  |  Next Article 

Journal of Bacteriology, July 2002, p. 3723-3733, Vol. 184, No. 13
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.13.3723-3733.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Assembly of Colicin A in the Outer Membrane of Producing Escherichia coli Cells Requires both Phospholipase A and One Porin, but Phospholipase A Is Sufficient for Secretion

Daniele Cavard*

Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Centre National de la Recherche Scientifique, 13402 Marseille Cedex 20, France

Received 15 January 2002/ Accepted 9 April 2002

Three oligomeric forms of colicin A with apparent molecular masses of about 95 to 98 kDa were detected on sodium dodecyl sulfate (SDS)-polyacrylamide gels loaded with unheated samples from colicin A-producing cells of Escherichia coli. These heat-labile forms, called colicins Au, were visualized both on immunoblots probed with monoclonal antibodies against colicin A and by radiolabeling. Cell fractionation studies show that these forms of colicin A were localized in the outer membrane whether or not the producing cells contained the cal gene, which encodes the colicin A lysis protein responsible for colicin A release in the medium. Pulse-chase experiments indicated that their assembly into the outer membrane, as measured by their heat modifiable migration in SDS gels, was an efficient process. Colicins Au were produced in various null mutant strains, each devoid of one major outer membrane protein, except in a mutant devoid of both OmpC and OmpF porins. In cells devoid of outer membrane phospholipase A (OMPLA), colicin A was not expressed. Colicins Au were detected on immunoblots of induced cells probed with either polyclonal antibodies to OmpF or monoclonal antibodies to OMPLA, indicating that they were associated with both OmpF and OMPLA. Similar heat-labile forms were obtained with various colicin A derivatives, demonstrating that the C-terminal domain of colicin A, but not the hydrophobic hairpin present in this domain, was involved in their formation.

* Mailing address: LISM-CNRS, 31 chemin Joseph Aiguier, BP 71, 13402 Marseille Cedex 20, France. Phone: 33 4 91 16 44 85. Fax: 33 4 91 71 21 24. E-mail: cavard{at}ibsm.cnrs-mrs.fr.

Journal of Bacteriology, July 2002, p. 3723-3733, Vol. 184, No. 13
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.13.3723-3733.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Cascales, E., Buchanan, S. K., Duche, D., Kleanthous, C., Lloubes, R., Postle, K., Riley, M., Slatin, S., Cavard, D. (2007). Colicin Biology. Microbiol. Mol. Biol. Rev. 71: 158-229 [Abstract] [Full Text]  
  • Cavard, D. (2004). Role of Cal, the colicin A lysis protein, in two steps of colicin A release and in the interaction with colicin A-porin complexes. Microbiology 150: 3867-3875 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»