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 Grys, T. E.
Right arrow Articles by Welch, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Grys, T. E.
Right arrow Articles by Welch, R. A.

 Previous Article  |  Next Article 

Journal of Bacteriology, July 2006, p. 4646-4653, Vol. 188, No. 13
0021-9193/06/$08.00+0     doi:10.1128/JB.01806-05
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Characterization of the StcE Protease Activity of Escherichia coli O157:H7

Thomas E. Grys, Laura L. Walters, and Rodney A. Welch*

Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Room 481 MSC, 1300 University Ave., Madison, Wisconsin 53706

Received 28 November 2005/ Accepted 12 April 2006

The StcE zinc metalloprotease is secreted by enterohemorrhagic Escherichia coli (EHEC) O157:H7 and contributes to intimate adherence of this bacterium to host cells, a process essential for mammalian colonization. StcE has also been shown to localize the inflammatory regulator C1 esterase inhibitor (C1-INH) to cell membranes. We tried to more fully characterize StcE activity to better understand its role in EHEC pathogenesis. StcE was active at pH 6.1 to 9.0, in the presence of NaCl concentrations ranging from 0 to 600 mM, and at 4°C to 55°C. Interestingly, antisera against StcE or C1-INH did not eliminate StcE cleavage of C1-INH. Treatment of StcE with the proteases trypsin, chymotrypsin, human neutrophil elastase, and Pseudomonas aeruginosa elastase did not eliminate StcE activity against C1-INH. After StcE was kept at 23°C for 65 days, it exhibited full proteolytic activity, and it retained 30% of its original activity after incubation for 8 days at 37°C. Together, these results show the StcE protease is a stable enzyme that is probably active in the environment of the colon. Additionally, kcat/Km data showed that StcE proteolytic activity was 2.5-fold more efficient with the secreted mucin MUC7 than with the complement regulator C1-INH. This evidence supports a model which includes two roles for StcE during infection, in which StcE acts first as a mucinase and then as an anti-inflammatory agent by localizing C1-INH to cell membranes.

* Corresponding author. Mailing address: Department of Medical Microbiology & Immunology, University of Wisconsin-Madison, Room 481 MSC, 1300 University Ave., Madison, WI 53706. Phone: (608) 263-2700. Fax: (608) 262-8418. E-mail: rawelch{at}wisc.edu.

Journal of Bacteriology, July 2006, p. 4646-4653, Vol. 188, No. 13
0021-9193/06/$08.00+0     doi:10.1128/JB.01806-05
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Bellmeyer, A., Cotton, C., Kanteti, R., Koutsouris, A., Viswanathan, V. K., Hecht, G. (2009). Enterohemorrhagic Escherichia coli suppresses inflammatory response to cytokines and its own toxin. Am. J. Physiol. Gastrointest. Liver Physiol. 297: G576-G581 [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»