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High-Pressure NMR Experiments for Detecting Protein Low-Lying Conformational States
Published on: June 29, 2021
Dramatic structural and thermodynamic consequences of repacking a protein's hydrophobic core
M A Willis1, B Bishop, L Regan
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.
Structure (London, England : 1993)
|February 24, 2001
Summary
Redesigning the hydrophobic core of the Rop protein resulted in a novel fold and altered thermodynamic properties. This study highlights the critical role of core packing in protein structure and stability.
Area of Science:
- Protein engineering
- Structural biology
- Biophysics
Background:
- Rop protein is a dimeric, four-helix bundle with a hydrophobic core suitable for redesign.
- Previous work created and characterized Rop variants with redesigned hydrophobic cores.
Purpose of the Study:
- To structurally and thermodynamically analyze Ala2Ile2-6, a Rop variant with an extensively redesigned hydrophobic core.
- To understand the impact of hydrophobic core redesign on protein fold and stability.
Main Methods:
- Structural analysis of Ala2Ile2-6.
- Thermodynamic analysis of Ala2Ile2-6 unfolding.
- Molecular modeling.
Main Results:
- Ala2Ile2-6 exhibits a new fold due to a protomer conformational flip.
- Ala2Ile2-6 has a higher melting temperature than wild-type Rop.
- Ala2Ile2-6 shows a smaller free-energy change upon unfolding compared to wild-type Rop.
Conclusions:
- Tight packing of core residues and favorable side chain rotamers are crucial for helix-helix interactions in four-helix bundles.
- Structural disorder at termini of Ala2Ile2-6 influences its folding enthalpy and entropy.
- Hydrophobic core redesign can significantly alter protein structure and thermodynamics.
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