Document Detail


High-pressure NMR reveals close similarity between cold and alcohol protein denaturation in ubiquitin.
MedLine Citation:
PMID:  23284170     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Proteins denature not only at high, but also at low temperature as well as high pressure. These denatured states are not easily accessible for experiment, because usually heat denaturation causes aggregation, whereas cold or pressure denaturation occurs at temperatures well below the freezing point of water or pressures above 5 kbar, respectively. Here we have obtained atomic details of the pressure-assisted, cold-denatured state of ubiquitin at 2,500 bar and 258 K by high-resolution NMR techniques. Under these conditions, a folded, native-like and a disordered state exist in slow exchange. Secondary chemical shifts show that the disordered state has structural propensities for a native-like N-terminal β-hairpin and α-helix and a nonnative C-terminal α-helix. These propensities are very similar to the previously described alcohol-denatured (A-)state. Similar to the A-state, (15)N relaxation data indicate that the secondary structure elements move as independent segments. The close similarity of pressure-assisted, cold-denatured, and alcohol-denatured states with native and nonnative secondary elements supports a hierarchical mechanism of folding and supports the notion that similar to alcohol, pressure and cold reduce the hydrophobic effect. Indeed, at nondenaturing concentrations of methanol, a complete transition from the native to the A-state can be achieved at ambient temperature by varying the pressure from 1 to 2,500 bar. The methanol-assisted pressure transition is completely reversible and can also be induced in protein G. This method should allow highly detailed studies of protein-folding transitions in a continuous and reversible manner.
Authors:
Navratna Vajpai; Lydia Nisius; Maciej Wiktor; Stephan Grzesiek
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2013-01-02
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  110     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-01-30     Completed Date:  2013-05-03     Revised Date:  2013-07-31    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E368-76     Citation Subset:  IM    
Affiliation:
Focal Area Structural Biology and Biophysics, Biozentrum, University of Basel, 4056 Basel, Switzerland.
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MeSH Terms
Descriptor/Qualifier:
Cold Temperature
Ethanol / chemistry
Humans
Kinetics
Magnetic Resonance Spectroscopy / methods*
Methanol / chemistry
Models, Molecular
Pressure
Protein Denaturation*
Protein Structure, Secondary
Protein Structure, Tertiary
Protein Unfolding*
Thermodynamics
Ubiquitin / chemistry*
Chemical
Reg. No./Substance:
0/Ubiquitin; 64-17-5/Ethanol; 67-56-1/Methanol
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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