Related Experiment Video
Updated: Aug 8, 2026
11:14
Combining Wet and Dry Lab Techniques to Guide the Crystallization of Large Coiled-coil Containing Proteins
Published on: January 6, 2017
A survey of protein-protein complex crystallizations
Sergei Radaev1, Sean Li, Peter D Sun
1Structural Immunology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, Maryland 20852, USA.
Summary
This study analyzed 650 protein-protein complex crystallizations, creating a database and identifying optimal conditions. Polyethylene glycol (PEG) and ammonium sulfate were key, with crystallization parameters being more restricted than for soluble proteins.
Area of Science:
- Structural Biology
- Biochemistry
- Crystallography
Background:
- Protein-protein complexes are crucial for cellular functions.
- Determining the structure of protein complexes is vital for understanding their mechanisms.
- Crystallization is a primary method for protein complex structure determination.
Purpose of the Study:
- To survey crystallization conditions for published protein-protein complexes.
- To establish a comprehensive Protein Complex Crystallization Database (PCCD).
- To define crystallization configuration-space boundaries for protein complexes.
Main Methods:
- Surveyed 650 published protein-protein complex structures from the Protein Data Bank (PDB).
- Compiled data into the Protein Complex Crystallization Database (PCCD).
- Performed statistical analysis to identify common crystallization parameters.
Main Results:
- Polyethylene glycol (PEG) based conditions were used in 70-80% of crystallizations, with PEG 3000-8000 being most frequent.
- Median PEG concentrations ranged from 10-20% and correlated inversely with molecular weight.
- Ammonium sulfate was the preferred salt precipitant (median 1.6 M), and optimal pH was 5.0-8.0.
- Crystallization space for complexes is more restricted than for soluble proteins, possibly due to stability/solubility issues.
Conclusions:
- Established PCCD and identified key crystallization conditions (PEG, ammonium sulfate, pH range).
- Defined boundaries for protein complex crystallization, highlighting narrower parameters compared to soluble proteins.
- Developed optimized screening strategies based on statistical analysis for improved protein complex crystallization success.
