PPCheck

PPCheck analyzes protein-protein interactions by quantifying structural and energetic characteristics of inter-atomic non-covalent interactions to assess stability and binding energetics of protein complexes.

Key Features:

• Identification of Protein-Protein Interactions: Identifies interaction sites between proteins using a curated dataset to improve accuracy.
• Prediction of Interaction Hotspots: Predicts critical interface regions (hotspots) that are essential for binding.
• Computational Alanine Scanning: Performs computational alanine scanning to assess residue importance by simulating mutations and evaluating effects on binding affinity.
• Native-Like Docking Pose Prediction: Predicts native-like docking poses of protein complexes to model interaction configurations.
• Residue Conservation Calculation: Calculates residue conservation at interaction sites to highlight evolutionary significance.

Scientific Applications:

• Phycocyanin interface analysis: Analyzes protein complexes such as phycocyanin interfaces to characterize interface composition and energetics.
• Interface composition insights: Reveals the prevalence of hydrophobic residues at protein-protein interfaces.
• Interface clustering: Identifies that a significant number of interface residues form "standard-size" clusters.
• Energetic and evolutionary studies: Dissects energetic contributions and conservation to inform structural stability of evolutionarily essential proteins and to support design of protein–bioactive compound interactions.

Methodology:

Analyzes inter-atomic non-covalent interactions including hydrogen bonds, van der Waals, and electrostatic contributions; computes hydrogen bond energy contribution (≈88% observed in phycocyanin interfaces), total binding energies, and normalized energy per residue (typically −6 to −14 kJ/mol); and performs computational alanine scanning and docking-pose prediction.