Document Detail

Trifluoroethanol increases the stability of Delta(5)-3-ketosteroid isomerase. 15N NMR relaxation studies.
MedLine Citation:
PMID:  11973332     Owner:  NLM     Status:  MEDLINE    
In the equilibrium unfolding process of Delta(5)-3-ketosteroid isomerase from Pseudomonas testosteroni by urea, it was observed that the enzyme stability increases by 2.5 kcal/mol in the presence of 5% trifluoroethanol (TFE). To elucidate the increased enzyme stability by TFE, the backbone dynamics of Delta(5)-3-ketosteroid isomerase were studied in the presence and absence of 5% TFE by (15)N NMR relaxation measurements, and the motional parameters (S(2), tau(e), and R(ex)) were extracted from the relaxation data using the model-free formalism. The presence of 5% TFE causes little change or a slight increase in the order parameters (S(2)) for a number of residues, which are located mainly in the dimer interface region. However, the majority of the residues exhibit reduced order parameters in the presence of 5% TFE, indicating that high frequency (pico- to nanosecond) motions are generally enhanced by TFE. The results suggest that the entropy can be an important factor for the enzyme stability, and the increase in entropy by TFE is partially responsible for the increased stability of Delta(5)-3-ketosteroid isomerase.
Sunggoo Yun; Do Soo Jang; Gildon Choi; Kwang S Kim; Kwan Yong Choi; Hee Cheon Lee
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2002-04-24
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  277     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-06-24     Completed Date:  2002-08-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  23414-9     Citation Subset:  IM    
Department of Chemistry, Pohang University of Science and Technology, Pohang, 790-784, Korea.
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MeSH Terms
Enzyme Stability
Magnetic Resonance Spectroscopy
Protein Folding
Steroid Isomerases / chemistry*
Trifluoroethanol / pharmacology*
Urea / pharmacology
Reg. No./Substance:
57-13-6/Urea; 75-89-8/Trifluoroethanol; EC 5.3.3.-/Steroid Isomerases; EC delta-isomerase

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