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Updated: Oct 23, 2025
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Derivatization of Protein Crystals with I3C using Random Microseed Matrix Screening
Published on: January 16, 2021
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Cesium based phasing of macromolecules: a general easy to use approach for solving the phase problem
Wolfgang Koelmel1, Jochen Kuper2, Caroline Kisker3
1Rudolf Virchow Center, University of Würzburg, Würzburg, Germany.
Scientific Reports
|August 24, 2021
Summary
Cesium chloride (CsCl) offers a versatile, low-cost solution to the macromolecular crystallography phase problem. This method aids in determining crystal structures by leveraging cesium
Area of Science:
- Crystallography
- Structural Biology
- Biophysics
Background:
- The phase problem remains a significant hurdle in macromolecular crystallography, hindering crystal structure determination.
- Despite advancements, efficient and accessible phasing strategies are continuously sought.
Purpose of the Study:
- To investigate the utility of cesium chloride (CsCl) for solving the phase problem in macromolecular crystallography.
- To develop and validate a CsCl-based phasing strategy applicable across different protein treatments.
Main Methods:
- Exploration of cesium incorporation during protein purification, crystallization, and cryo-protection.
- Development of a step-wise CsCl application protocol, including a 'quick-soak' method and combined purification/cryo-protection approaches.
- Application of the CsCl strategy to Lysozyme and a TFIIH p62 PH domain construct for de novo structure determination.
Main Results:
- Successful implementation of CsCl-based phasing strategies for two distinct protein systems.
- Demonstrated versatility and ease of use of CsCl for phasing, applicable at various experimental stages.
Conclusions:
- Cesium chloride provides a general, cost-effective, and user-friendly phasing strategy for macromolecular crystallography.
- The developed CsCl protocols facilitate de novo structure determination, overcoming phase ambiguity.
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