Stabilizing Salt-Bridge Enhances Protein Thermostability by Reducing the Heat Capacity Change of Unfolding
2011

How Salt-Bridges Help Proteins Stay Stable at High Temperatures

publication Evidence: high

Author Information

Author(s): Chan Chi-Ho Yu, Tsz-Ha Wong, Kam-Bo Wong

Primary Institution: School of Life Sciences, Centre for Protein Science and Crystallography, The Chinese University of Hong Kong

Hypothesis

The study investigates how salt-bridges contribute to the thermostability of proteins by reducing the heat capacity change of unfolding.

Conclusion

The presence of stabilizing salt-bridges in thermophilic proteins enhances their thermostability by reducing the heat capacity change during unfolding.

Supporting Evidence

  • The study demonstrated that the salt-bridges E6/R92 and E62/K46 stabilize the protein by approximately 2–5 kJ mol−1.
  • Each salt-bridge contributed to a reduction of ΔCp by 0.8–1.0 kJ mol−1 K−1.
  • The pair-wise interaction energy of the salt-bridges was found to be insensitive to temperature changes.

Takeaway

This study shows that certain connections in proteins, called salt-bridges, help them stay strong and stable even when it's really hot.

Methodology

The study used double mutant cycles to analyze the temperature-dependency of pair-wise interaction energies and the contribution of salt-bridges to heat capacity changes in a thermophilic ribosomal protein.

Digital Object Identifier (DOI)

10.1371/journal.pone.0021624

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