Chapter

Chapter 13.3 Translation functions

Crystallography of biological macromolecules

Second Online Edition (2012)

Part 13. Molecular replacement

  1. L. Tong

Published Online: 14 APR 2012

DOI: 10.1107/97809553602060000841

International Tables for Crystallography

International Tables for Crystallography

How to Cite

Tong, L. 2012. Translation functions. International Tables for Crystallography. F:13:13.3:347–351.

Author Information

  1. Department of Biological Sciences, Columbia University, New York, NY 10027, USA

Publication History

  1. Published Online: 14 APR 2012

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Abstract

Translation functions are used to determine the positions of search models by the molecular‐replacement method. The functions are generally based on the comparisons of observed and calculated structure‐factor amplitudes (R factor and correlation coefficient) or the comparisons of the corresponding Patterson functions. Combined molecular replacement is a limited six‐dimensional search where sampling of the rotational degrees of freedom is guided by the rotation function. Evaluating the packing arrangement of the model in the crystal is an important part of the molecular‐replacement calculation. The locked translation function can be used in cases where the crystal contains point‐group noncrystallographic symmetry.

Keywords:

  • Cheshire group;
  • Patterson‐correlation translation function;
  • R‐factor translation function;
  • combined molecular replacement;
  • correlation‐coefficient translation function;
  • locked translation function;
  • molecular replacement;
  • phased translation function;
  • translation functions