Decoding the intricate network of molecular interactions of a hyperstable engineered biocatalyst

Area of Science:

• Protein engineering
• Biocatalysis
• Structural biology

Background:

• Designing protein catalysts with enhanced stability is crucial for research and industrial applications.
• Previous computational design yielded the thermostable haloalkane dehalogenase DhaA115 with 11 mutations.

Purpose of the Study:

• To elucidate the structural basis of hyperstabilization in DhaA115.
• To inform the development of predictive algorithms for designing thermostable proteins.

Main Methods:

• X-ray crystallography (1.55 Å and 1.6 Å resolutions)
• Molecular dynamics simulations
• Phylogenetic analysis
• Force-field calculations

Main Results:

• Detailed structures of DhaA115 revealed an intricate interaction network stabilizing the αβα-sandwich fold.
• Surface mutations induced long-range cooperative backbone changes, forming a double-lock system.
• This system restricted active site access tunnels but maintained ligand transport efficacy, confirmed by krypton derivative crystal studies.

Conclusions:

• The study identifies key thermostabilization effects driven by cooperative interactions.
• Provides a structural foundation for the rational design of novel, highly stable protein catalysts.
• Highlights the potential of computational design in enzyme technology.