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

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, August 2004, p. 4840-4847, Vol. 70, No. 8
0099-2240/04/$08.00+0     DOI: 10.1128/AEM.70.8.4840-4847.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Protein Folding Failure Sets High-Temperature Limit on Growth of Phage P22 in Salmonella enterica Serovar Typhimurium

Massachusetts Institute of Technology, Cambridge,¹ Woods Hole Oceanographic Institution, Woods Hole, Massachusetts²

Received 16 January 2004/ Accepted 19 April 2004

The high-temperature limit for growth of microorganisms differs greatly depending on their species and habitat. The importance of an organism's ability to manage thermal stress is reflected in the ubiquitous distribution of the heat shock chaperones. Although many chaperones function to reduce protein folding defects, it has been difficult to identify the specific protein folding pathways that set the high-temperature limit of growth for a given microorganism. We have investigated this for a simple system, phage P22 infection of Salmonella enterica serovar Typhimurium. Production of infectious particles exhibited a broad maximum of 150 phage per cell when host cells were grown at between 30 and 39°C in minimal medium. Production of infectious phage declined sharply in the range of 40 to 41°C, and at 42°C, production had fallen to less than 1% of the maximum rate. The host cells maintained optimal division rates at these temperatures. The decrease in phage infectivity was steeper than the loss of physical particles, suggesting that noninfectious particles were formed at higher temperatures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a decrease in the tailspike adhesins assembled on phage particles purified from cultures incubated at higher temperatures. The infectivity of these particles was restored by in vitro incubation with soluble tailspike trimers. Examination of tailspike folding and assembly in lysates of phage-infected cells confirmed that the fraction of polypeptide chains able to reach the native state in vivo decreased with increasing temperature, indicating a thermal folding defect rather than a particle assembly defect. Thus, we believe that the folding pathway of the tailspike adhesin sets the high-temperature limit for P22 formation in Salmonella serovar Typhimurium.