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Polyalanine reconstruction from Calpha positions using the program CALPHA can aid initial phasing of data by
1The Laboratory of Molecular Biophysics, Oxford, England. robest@biop.ox.ac.uk
Acta Crystallographica. Section D, Biological Crystallography
|August 10, 2004
Summary
Protein structure reconstruction is improved using the CALPHA database program. This method accurately rebuilds protein models and enhances orientation searches for molecular replacement, aiding structural biology research.
Area of Science:
- Structural biology
- Computational biology
- Biophysics
Background:
- Protein Calpha positions offer a scaffold for reconstructing complete protein models.
- Database reconstruction is a convenient and reliable method for model rebuilding.
Purpose of the Study:
- To introduce the CALPHA database reconstruction program.
- To assess the accuracy and reliability of CALPHA through test reconstructions.
- To explore CALPHA's utility in automating refinement and molecular replacement.
Main Methods:
- Database reconstruction using the CALPHA program.
- Test reconstructions of well-refined protein structures.
- Comparison of Calpha-only and reconstructed polyalanine models for HIV-1 reverse transcriptase in cross-rotation and translation function searches.
Main Results:
- Backbone atoms were repositioned within 0.3 Å of original positions.
- Main-chain torsion angles were regenerated within 15 degrees.
- CALPHA polyalanine models showed increased selectivity for correct orientations in molecular replacement searches.
Conclusions:
- The CALPHA program provides accurate and reliable protein model reconstruction.
- CALPHA facilitates automation of refinement procedures.
- CALPHA models are effective for molecular replacement, particularly for orientation searches.