Differential scanning calorimetry was used to study the thermodynamics of denaturation of protein complexes for which the free energy stabilizing the complexes varied between -8 and -16 kcal/mol. The proteins studied were the ribonucleases barnase and binase, their inhibitor barstar and mutants thereof, and complexes between the two. The results are in good agreement with the model developed by Brandts and Lin for studying the thermodynamics of denaturation for tight complexes between two proteins which undergo two-state thermal unfolding transitions.
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http://dx.doi.org/10.1016/s0301-4622(03)00103-0 | DOI Listing |
Protein Sci
February 2025
Amherst College, Amherst, Massachusetts, USA.
Hydrogen exchange mass spectrometry (HXMS) is a powerful tool to understand protein folding pathways and energetics. However, HXMS experiments to date have used exchange conditions termed EX1 or EX2 which limit the information that can be gained compared to the more general EXX exchange regime. If EXX behavior could be understood and analyzed, a single HXMS timecourse on an intact protein could fully map its folding landscape without requiring denaturation.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Biozentrum, University of Basel, Spitalstrasse 41, CH-4056 Basel, Switzerland.
The thermodynamics of pressure-induced protein denaturation could so far not be directly compared with protein denaturation induced by temperature or chemical agents. Here, we provide a new cooperative model for pressure-induced protein denaturation that allows the quantitative comparison of all three denaturing processes based on their free energy, enthalpy, entropy, and cooperativity. As model proteins, we use apolipoprotein A-1 and lysozyme.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
Knotted proteins have a unique topological feature with an open knot, and the physiological significance of these knots remains elusive. In addition, these proteins challenge our understanding of the protein folding process, and whether they retain their native state during unfolding/refolding cycles like other proteins is debated. Most folding studies on knotted proteins have been performed on 3 and 5 knots, monitoring the tryptophan fluorescence.
View Article and Find Full Text PDFQ Rev Biophys
January 2025
Elettra Sincrotrone Trieste, Italy.
Yeast frataxin (Yfh1) is a small natural protein from yeast that has the unusual property of undergoing cold denaturation at temperatures above the freezing point of water when under conditions of low ionic strength. This peculiarity, together with remarkable resilience, allows the determination, for the whole protein as well as for individual residues, of the stability curve, that is the temperature dependence of the free energy difference between the unfolded and folded forms. The ease of measuring stability curves without the need to add denaturants or introduce destabilizing mutations makes this protein an ideal 'tool' for investigating the influence of many environmental factors on protein stability.
View Article and Find Full Text PDFBioorg Chem
February 2025
Department of Bioengineering, Gebze Technical University, 41400, Gebze, Kocaeli, Türkiye; BAUZYME Biotechnology Co., Gebze Technical University Technopark, 41400, Gebze, Kocaeli, Türkiye. Electronic address:
α-Amylases, constituting a significant share of the enzyme market, are mainly synthesized by the genus Bacillus. Enzymes tailored for specific industrial applications are needed to meet the growing demand across a range of industries, and thus finding new amylases and optimizing the ones that already exist are extremely important. This study reports the successful expression, characterization and immobilization of P.
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