Methods to refine macromolecular structures in cases of severe diffraction anisotropy

Area of Science:

• Crystallography
• Structural Biology
• Biophysics

Background:

• Diffraction anisotropy, varying diffraction quality with reciprocal lattice direction, hinders macromolecular structure determination.
• Severe anisotropy leads to poor electron density maps, stalled model building, and suboptimal refinement statistics.

Purpose of the Study:

• To present a combined approach for diagnosing and compensating for diffraction anisotropy.
• To provide guidance on implementing methods to facilitate refinement of macromolecular structures with anisotropic data.

Main Methods:

• Implementation of a diffraction anisotropy server combining published methods.
• Application of ellipsoidal resolution boundaries, anisotropic scaling, and B-factor sharpening.
• Diagnosis of anisotropy degree and data compensation.

Main Results:

• The diffraction anisotropy server aids in overcoming challenges posed by anisotropic diffraction data.
• Improved data quality and refinement statistics are achievable through the implemented methods.

Conclusions:

• The diffraction anisotropy server offers a practical solution for refining macromolecular structures with severely anisotropic data.
• Implementing these methods facilitates detailed analysis and model improvement in crystallography.