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Thermally versus Chemically Denatured Protein States
Abhishek Narayan,
Published in American Chemical Society
2019
PMID: 31083972
Volume: 58
   
Issue: 21
Pages: 2519 - 2523
Abstract
Protein unfolding thermodynamic parameters are conventionally extracted from equilibrium thermal and chemical denaturation experiments. Despite decades of work, the degree of structure and the compactness of denatured states populated in these experiments are still open questions. Here, building on previous works, we show that thermally and chemically denatured protein states are distinct from the viewpoint of far-ultraviolet circular dichroism experiments that report on the local conformational status of peptide bonds. The differences identified are independent of protein length, structural class, or experimental conditions, highlighting the presence of two sub-ensembles within the denatured states. The sub-ensembles, UT and UD for thermally induced and denaturant-induced unfolded states, respectively, can exclusively exchange populations as a function of temperature at high chemical denaturant concentrations. Empirical analysis suggests that chemically denatured states are ∼50% more expanded than the thermally denatured chains of the same protein. Our observations hint that the strength of protein backbone-backbone interactions and identity versus backbone-solvent/co-solvent interactions determine the conformational distributions. We discuss the implications for protein folding mechanisms, the heterogeneity in relaxation rates, and folding diffusion coefficients. © 2019 American Chemical Society.
About the journal
JournalData powered by TypesetBiochemistry
PublisherData powered by TypesetAmerican Chemical Society
ISSN00062960
Open AccessYes
Concepts (22)
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    Conformations
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    Dichroism
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    Proteins
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    Structure (composition)
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    BACKBONE INTERACTIONS
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    CHEMICAL DENATURANTS
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    CHEMICAL DENATURATION
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    CONFORMATIONAL DISTRIBUTION
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    Empirical analysis
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    Experimental conditions
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    PROTEIN FOLDING MECHANISMS
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    Thermodynamic parameter
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    Denaturation
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    Article
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    Circular dichroism
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    Conformational transition
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    Phase transition
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    Priority journal
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    Protein denaturation
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    Protein folding
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    PROTEIN UNFOLDING
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    Thermodynamics