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Related Experiment Video

Updated: Jun 14, 2026

Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator

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Published on: January 28, 2019

Experimental phasing: best practice and pitfalls.

Airlie J McCoy¹, Randy J Read

¹Cambridge Institute for Medical Research, University of Cambridge, Hills Road, Cambridge CB2 OXY, England. ajm201@cam.ac.uk

Acta Crystallographica. Section D, Biological Crystallography

|April 13, 2010

Summary

This summary is machine-generated.

This review covers experimental phasing for protein crystal structure determination, highlighting its connection to density modification and refinement. It details common challenges and introduces advanced phasing methods for improved substructure completion.

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Area of Science:

Structural Biology
Crystallography

Background:

Experimental phasing is crucial for determining protein crystal structures when direct methods fail.
Understanding the interplay between phasing, density modification, and refinement is key for accurate structure determination.

Purpose of the Study:

To review advancements in experimental phasing techniques for protein structure determination.
To discuss theoretical aspects, practical challenges, and new methodologies in experimental phasing.

Main Methods:

Review of established and emerging experimental phasing strategies.
Discussion of substructure determination, map generation coefficients, and enantiomorph/symmetry identification.
Introduction of novel phasing coefficients for single-wavelength anomalous diffraction (SAD) phasing and substructure completion.

Main Results:

Emphasizes the continuum between experimental phasing, density modification, model building, and refinement.
Details common pitfalls in experimental phasing, including enantiomorph determination, symmetry identification, and crystal twinning.
Presents new map coefficients for SAD phasing and their application in substructure completion using Phaser software.

Conclusions:

Experimental phasing remains a vital component of the protein structure determination pipeline.
Addressing common pitfalls and utilizing advanced methods like those presented can improve the success rate of structure determination.
The supplementary materials aim to aid in teaching best practices for experimental phasing.