Structural Proteomics-Based Deciphering of Hydrophobic Packing Fingerprints Informing Protein Thermostability in TIM...

Area of Science:

• Structural biology and bioinformatics
• Protein folding and stability
• Computational proteomics

Background:

• Tightly packed hydrophobic cores are crucial for globular protein stability.
• Quantitative rules for hydrophobic cluster formation and stability are poorly understood.
• Existing models struggle with accuracy and interpretability in predicting cluster stability.

Purpose of the Study:

• To develop a quantitative platform, qPacking, for analyzing hydrophobic clusters in proteins.
• To define and quantify hydrophobic packing descriptors (HPDs) for key hydrophobic residues.
• To systematically investigate hydrophobic clusters within the triosephosphate isomerase (TIM) barrel fold.

Main Methods:

• Development of the qPacking quantitative platform.
• Definition of five hydrophobic packing descriptors (HPDs) for residues A, V, I, L, M.
• Systematic quantification and analysis of hydrophobic clusters in TIM barrels.

Main Results:

• Hydrophobic clusters in TIM barrels are primarily in α-β regions, not β-barrel regions.
• Thermophilic TIM barrels show larger, denser hydrophobic clusters than nonthermophilic ones.
• Evolutionary analysis reveals a trade-off between packing area and steric constraints in cluster formation.

Conclusions:

• qPacking and HPDs offer a quantitative framework for studying protein hydrophobic cores.
• The findings provide insights into the structural basis of protein thermal stability.
• This approach can aid in optimizing protein stability for biotechnological applications.