Chapter 5. Methods for Solving the Phase Problem

  1. Dr. Albrecht Messerschmidt

Published Online: 5 JAN 2007

DOI: 10.1002/9783527610129.ch5

X-Ray Crystallography of Biomacromolecules: A Practical Guide

X-Ray Crystallography of Biomacromolecules: A Practical Guide

How to Cite

Messerschmidt, A. (2007) Methods for Solving the Phase Problem, in X-Ray Crystallography of Biomacromolecules: A Practical Guide, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany. doi: 10.1002/9783527610129.ch5

Author Information

  1. Max-Planck-Institue of Biochemistry, Department of Proteomics and Signal Transduction, Research Group: Structural Proteomics, Am Klopferspitz 18, 82152 Martinsried, Germany

Publication History

  1. Published Online: 5 JAN 2007
  2. Published Print: 15 DEC 2007

ISBN Information

Print ISBN: 9783527313969

Online ISBN: 9783527610129



  • methods for solving the phase problem;
  • isomorphous replacement;
  • anomalous scattering;
  • determination of heavy-atom positions;
  • phase calculations;
  • Patterson search methods (molecular replacement);
  • computer programs


This chapter contains sections titled:

  • Isomorphous Replacement

    • Preparation of Heavy-Metal Derivatives

    • Single Isomorphous Replacement

    • Multiple Isomorphous Replacement

  • Anomalous Scattering

    • Theoretical Background

    • Experimental Determination

    • Breakdown of Friedel's Law

    • Anomalous Difference Patterson Map

    • Phasing Including Anomalous Scattering Information

    • The Multiwavelength Anomalous Diffraction (MAD) Technique

    • Determination of the Absolute Configuration

  • Determination of Heavy-Atom Positions

    • Vector Verification Procedures

    • Direct Methods

  • Phase Calculation

    • Refinement of Heavy-Atom Parameters

    • Protein Phases

    • Maximum-Likelihood Parameter Refinement and Phase Calculation

    • Cross-Phasing of Heavy-Atom Derivatives or Anomalous Dispersion Data

  • Patterson Search Methods (Molecular Replacement)

    • Rotation Function

    • Locked Rotation Function

    • Translation Function

      • R-Factor and Correlation-Coefficient Translation Functions

      • Patterson-Correlation Translation Function

      • Phased Translation Function

    • Computer Programs for Molecular Replacement