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Effects of conjugated and unconjugated bile acids on the activity of the Vibrio cholerae porin OmpT.
MedLine Citation:
PMID:  21067451     Owner:  NLM     Status:  In-Data-Review    
Abstract During infection, the enteric pathogen Vibrio cholerae encounters a bile-containing environment. Previous studies have shown that bile and/or bile acids exert several effects on the virulence and physiology of the bacterial cells. These observations have led to the suggestion that bile acids may play a signaling role in infection. We have previously reported that the bile component deoxycholic acid blocks the general diffusion porin OmpT in a dose-dependent manner, presumably as it transits through the pore. V. cholerae colonizes the distal jejunum and ileum, where a mixture of various conjugated and unconjugated bile acids are found. In this work, we have used patch clamp electrophysiology to investigate the effects of six bile acids on OmpT. Two bile acids (deoxycholic and chenodeoxycholic acids) were found to block OmpT at physiological concentrations below 1 mM, while glycodeoxycholic acid was mildly effective and cholic, lithocholic and taurodeoxycholic acids were ineffective in this range. The block was also voltage-dependent. These observations suggest the presence of a specific binding site inside the OmpT pore. Since deconjugation is due to the activity of the endogenous flora, the preferential uptake of some unconjugated bile acids by OmpT may signal the presence of a hospitable environment. The results are also discussed in terms of the possible molecular interactions between the penetrating bile acid molecule and the channel wall.
Melissa Pagel; Anne H Delcour
Publication Detail:
Type:  Journal Article     Date:  2010-11-11
Journal Detail:
Title:  Molecular membrane biology     Volume:  28     ISSN:  1464-5203     ISO Abbreviation:  Mol. Membr. Biol.     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2011-01-11     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9430797     Medline TA:  Mol Membr Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  69-78     Citation Subset:  IM    
Department of Biology & Biochemistry, University of Houston, Houston, Texas, USA.
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