Document Detail


Temperature-induced conformational changes within the regulatory loops L1-L2-LA of the HtrA heat-shock protease from Escherichia coli.
MedLine Citation:
PMID:  19615474     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The present investigation was undertaken to characterize mechanism of thermal activation of serine protease HtrA (DegP) from Escherichia coli. We monitored the temperature-induced structural changes within the regulatory loops L1, L2 and LA using a set of single-Trp HtrA mutants. The accessibility of each Trp residue to aqueous medium at temperature range 25-45 degrees C was assessed by steady-state fluorescence quenching using acrylamide and these results in combination with mean fluorescence lifetimes (tau) and wavelength emission maxima (lambda(em)max) were correlated with the induction of the HtrA proteolytic activity. Generally the temperature shift caused better exposure of Trps to the quencher; although, each of the loops was affected differently. The LA loop seemed to be the most prone to temperature-induced conformational changes and a significant opening of its structure was observed even at the lowest temperatures tested (25-30 degrees C). To the contrary, the L1 loop, containing the active site serine, remained relatively unchanged up to 40 degrees C. The L2 loop was the most exposed element and showed the most pronounced changes at temperatures exceeding 35 degrees C. Summing up, the HtrA structure appears to open gradually, parallel to the gradual increase of its proteolytic activity.
Authors:
Anna Sobiecka-Szkatula; Agnieszka Polit; Andrea Scire; Artur Gieldon; Fabio Tanfani; Zaneta Szkarlat; Jerzy Ciarkowski; Dorota Zurawa-Janicka; Joanna Skorko-Glonek; Barbara Lipinska
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-07-14
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1794     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  2009 Nov 
Date Detail:
Created Date:  2009-09-23     Completed Date:  2009-12-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  1573-82     Citation Subset:  IM    
Affiliation:
Department of Biochemistry, University of Gdansk, Kladki 24, 80-822 Gdansk, Poland.
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MeSH Terms
Descriptor/Qualifier:
Circular Dichroism
Escherichia coli / genetics
Heat-Shock Proteins / chemistry*,  genetics,  metabolism
Heat-Shock Response / genetics
Periplasmic Proteins / chemistry*,  genetics,  metabolism
Protein Conformation / drug effects
Protein Denaturation
Serine Endopeptidases / chemistry*,  genetics,  metabolism
Spectroscopy, Fourier Transform Infrared
Chemical
Reg. No./Substance:
0/Heat-Shock Proteins; 0/Periplasmic Proteins; EC 3.4.21.-/DegP protease; EC 3.4.21.-/Serine Endopeptidases

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