Heat-induced structural and chemical changes to a computationally designed miniprotein.

Area of Science:

• Protein engineering
• Biochemistry
• Structural biology

Background:

• De novo designed miniproteins are promising drug candidates due to their high affinity, small size, and stability.
• Limited understanding exists regarding the dynamics and heat-induced changes in these miniproteins.

Purpose of the Study:

• Investigate unintended heat-induced structural and chemical alterations in a stable model miniprotein (EHEE_rd2_0005).
• Gain insights into miniprotein dynamics at elevated temperatures for improved future designs.

Main Methods:

• Nuclear magnetic resonance (NMR) spectroscopy to probe dynamics and chemical changes.
• Capillary electrophoresis and mass spectrometry (MS) to validate deamidation.
• Replica exchange molecular dynamics simulations to model hydrogen bond disruption.

Main Results:

• NMR revealed dynamics across multiple time and temperature scales.
• Elevated temperatures induced spontaneous chemical deamidation and accelerated hydrogen exchange.
• Observed signal loss in NMR spectra correlated with local unfolding, validated by simulations.

Conclusions:

• High stability in miniproteins may lead to long-lived alternate conformational states.
• Understanding heat-induced changes is crucial for the rational design of stable protein therapeutics.
• Identified key principles for developing next-generation miniprotein inhibitors.