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Relaxation of the resolution requirements for direct-methods phasing.

David A Langs¹, Herbert A Hauptman

¹Department of Structural Biology, Hauptman-Woodward Medical Research Institute, Buffalo, NY 14203, USA. langs@hwi.buffalo.edu

Acta Crystallographica. Section A, Foundations of Crystallography

|June 23, 2011

Summary

Shake-and-bake phasing now solves larger crystal structures using improved methods. This technique enhances crystal structure determination with lower resolution diffraction data, enabling analysis of previously unsolvable complex molecules.

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Area of Science:

Crystallography
Structural Biology
Materials Science

Background:

Shake-and-bake phasing methods enable ab initio crystal structure solution for complex molecules.
Current methods require high-resolution diffraction data (at least 1.2 Å) for successful structure determination.

Purpose of the Study:

To improve shake-and-bake phasing methods for broader applicability.
To enable crystal structure solution using lower resolution diffraction data.

Main Methods:

Introduction of a new target function, R(2)(φ(h)), into the shake-and-bake procedure.
Implementation of a real difference map strategy to enhance phasing capabilities.

Main Results:

The modified shake-and-bake procedure successfully lowers the resolution requirement to approximately 1.5 Å.
This advancement allows for the solution of crystal structures twice the size of those previously manageable.

Conclusions:

The enhanced shake-and-bake method expands the scope of crystal structure analysis.
This breakthrough facilitates the study of larger and more complex molecular structures with accessible diffraction data.