Document Detail


Stochastic kinetic analysis of the Escherichia coli stress circuit using sigma(32)-targeted antisense.
MedLine Citation:
PMID:  11536134     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A stochastic Petri net model was developed for simulating the sigma(32) stress circuit in E. coli. Transcription factor sigma(32) is the principal regulator of the response of E. coli to heat shock. Stochastic Petri net (SPN) models are well suited for kinetics characterization of fluxes in biochemical pathways. Notably, there exists a one-to-one mapping of model tokens and places to molecules of particular species. Our model was validated against experiments in which ethanol (inducer of heat shock response) and sigma(32)-targeted antisense (downward regulator) were used to perturb the sigma(32) regulatory pathway. The model was also extended to simulate the effects of recombinant protein production. Results show that the stress response depends heavily on the partitioning of sigma(32) within the cell; that is, sigma(32) becomes immediately available to mediate a stress response because it exists primarily in a sequestered, inactive form, complexed with chaperones DnaK, DnaJ, and GrpE. Recombinant proteins, however, also compete for chaperone proteins, particularly when folded improperly. Our simulations indicate that when the expression of recombinant protein has a low requirement for DnaK, DnaJ, and GrpE, the overall sigma(32) levels may drop, but the level of heat shock proteins will increase. Conversely, when the overexpressed recombinant protein has a strong requirement for the chaperones, a severe response is predicted. Interestingly, both cases were observed experimentally.
Authors:
R Srivastava; M S Peterson; W E Bentley
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Biotechnology and bioengineering     Volume:  75     ISSN:  0006-3592     ISO Abbreviation:  Biotechnol. Bioeng.     Publication Date:  2001 Oct 
Date Detail:
Created Date:  2001-09-05     Completed Date:  2001-12-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7502021     Medline TA:  Biotechnol Bioeng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  120-9     Citation Subset:  IM    
Copyright Information:
Copyright 2001 John Wiley & Sons, Inc.
Affiliation:
Department of Chemical Engineering, University of Maryland, College Park, Maryland 20742, USA.
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MeSH Terms
Descriptor/Qualifier:
Antisense Elements (Genetics)
Computer Simulation
Escherichia coli / genetics*,  metabolism*
Ethanol
Gene Expression Regulation, Bacterial
Heat-Shock Proteins / genetics,  metabolism
Models, Biological*
Recombinant Proteins / genetics
Sigma Factor / genetics*,  metabolism*
Solvents
Stochastic Processes
Chemical
Reg. No./Substance:
0/Antisense Elements (Genetics); 0/Heat-Shock Proteins; 0/Recombinant Proteins; 0/Sigma Factor; 0/Solvents; 64-17-5/Ethanol

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