PREDITOR

PREDITOR predicts protein backbone and side-chain torsion angles from NMR chemical shift data and sequence homology to provide torsion angle restraints for NMR structure determination.

Key Features:

• Torsion Angle Prediction: Predicts φ (phi), ψ (psi), ω (omega), and χ₁ (chi-1) torsion angles and reports associated predicted errors.
• Input Types: Accepts protein sequences or NMR chemical shift data as input.
• Sequence Homology / Alignment: Integrates sequence alignment techniques and sequence homology for mapping to known structures.
• Chemical Shift Analysis: Performs advanced chemical shift analysis to derive torsion angle information.
• Automated Chemical Shift Re-referencing: Automatically re-references chemical shift data to a standard reference to improve prediction accuracy.
• PDB Structure Mapping: Leverages Protein Data Bank (PDB) structure mapping to enhance dihedral angle prediction accuracy.
• Proline Cis/Trans Prediction: Predicts proline cis/trans states relevant to local conformation.
• Error Estimation: Provides predicted errors for individual torsion angle restraints.
• Output Compatibility: Produces torsion angle restraints compatible with CNS, XPLOR, AMBER, and CYANA for structure refinement.
• Performance: Processes predictions in under 40 seconds per protein, with reported accuracies of 88% of φ/ψ predictions within 30°, 84% of χ₁ predictions accurate, 99.97% of ω predictions correct, and performance reported as up to 35× faster and up to 20% more accurate than existing methods.

Scientific Applications:

• Structure Refinement: Provides torsion angle restraints for integration into CNS, XPLOR, AMBER, and CYANA to refine protein structures.
• NMR Structure Determination: Facilitates NMR structure determination by supplying rapid torsion angle restraints to reduce manual effort.
• Conformational Analysis: Supports analysis of proline cis/trans states and local backbone/side-chain conformations relevant to folding and stability.

Methodology:

Combines sequence alignment/sequence homology mapping and advanced chemical shift analysis with automated chemical shift re-referencing, PDB structure mapping, and proline cis/trans state prediction to compute φ, ψ, ω, and χ₁ torsion angles and associated prediction errors.