Resolution: Difference between revisions
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Once refinement of the electron density map is completed, the amount of electron density at the position of each atom determines that atom's [[Temperature|B factor or temperature value]]. | Once refinement of the electron density map is completed, the amount of electron density at the position of each atom determines that atom's [[Temperature|B factor or temperature value]]. | ||
==Resolution and structure quality== | |||
The higher the resolution of the diffraction data, the more measurements are present to base the model on. Also, an increase in resolution means that a given reflection is measured with less error than in a corresponding lower quality diffraction data set. As a consequence, the model can be built with fewer systematic errors (such as missing or misplaced atoms) and with less average coordinate error. The coordinate error (roughly defined as how different two models would be based on the same crystals, but independent measurement, model building and refinement) correlates with resolution, but is of a different order of magnitude. It is also influenced by completeness of the data (higher is better), the free R-factor of the refinement (lower is better), and the completeness of the model (higher is better). A typical crystallographic model based on 2.0 Å data has a coordinate error of less than 0.2 Å. (http://www.ccp4.ac.uk/newsletters/newsletter33/murshudov.html) | |||
==Determination of Resolution== | ==Determination of Resolution== | ||
