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A Protocol for Computer-Based Protein Structure and Function Prediction
Published on: November 3, 2011
Potential use of real-space refinement in protein structure determination
1Department of Chemistry and Institute of Molecular Biophysics, Florida State University, Tallahassee 32306-3015, USA. chapman@sb.fsu.edu
Summary
Real-space refinement enhances protein structure modeling by improving electron-density maps. This method offers a faster, more accurate alternative to traditional reciprocal-space refinement for structural biology.
Area of Science:
- Structural Biology
- Computational Biology
- Biophysics
Background:
- Conventional reciprocal-space refinement is standard for protein structure determination.
- Electron-density maps can be of poor quality, hindering accurate refinement.
- Real-space refinement offers an alternative approach to model building.
Purpose of the Study:
- To evaluate real-space refinement as a complementary technique to reciprocal-space refinement.
- To assess the utility of real-space refinement for protein structures with poor electron-density maps.
- To compare the efficiency and accuracy of combined refinement protocols.
Main Methods:
- Testing refinement protocols using free R-factor estimates.
- Alternating real-space and reciprocal-space refinement steps.
- Utilizing experimental maps and calculating 2Fo - Fc maps.
- Applying the method to the HMG-CoA reductase structure.
Main Results:
- Real-space refinement is a valuable addition to reciprocal-space refinement, even with poor electron-density maps.
- Alternating real- and reciprocal-space refinement yielded a model with a 1.5% better free R factor than exhaustive reciprocal-space refinement.
- The automated protocol achieved results comparable to intensive manual rebuilding and refinement.
Conclusions:
- Real-space refinement protocols can significantly improve protein structure model quality.
- Combining real-space and reciprocal-space refinement offers an efficient and effective strategy.
- This approach is particularly beneficial for structures with challenging electron-density maps.
