Keep it together: Restraints in crystallographic refinement of macromolecule-ligand complexes

Abstract

A short introduction is provided to the concept of restraints in macromolecular crystallographic refinement. A typical ligand restraint-generation process is then described, covering types of input, the methodology and the mechanics behind the software in general terms, how this has evolved over recent years and what to look for in the output. Finally, the currently available restraint-generation software is compared, concluding with some thoughts for the future.An overview of the process of ligand restraint generation for macromolecular crystallographic refinement is given.