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. Author manuscript; available in PMC: 2009 May 13.
Published in final edited form as: Photochem Photobiol. 2009 Jan 19;85(2):425–430. doi: 10.1111/j.1751-1097.2008.00516.x

Table 1.

Diffraction precision indexes (dpi)* for selected GPCR structures.

PDB ID DPI‡
1U19 0.15
1GZM 0.83
2I37 1.43
3CAP 0.25
2Z73 0.28
2VT4 0.79
2RH1 0.30
3D4S 0.42
*

DPI is a stringent measure of the certainty of atomic positions within an X-ray structure and indicates the minimal significant difference between two structures.

†

DPI is calculated as follows: dpi = 1*(Ni/Nobs)1/2C-1/3Rfreedmin where Ni is the number of fully occupied sites within the asymetric unit, Nobs is the number of observations, and C is the completeness of the dataset.

‡

Structural precision (DPI) was calculated using the electron density server (EDS) if possible (27). For 3CAP and 2I37 the program SFC HECK was used because the EDS fails to calculate maps for 2I37 and 3CAP. For 1U19, the program ESCET was used as there are no structure factors deposited (53). Interestingly, the re-refinement of the 1GZM structure in the higher symmetry space group p64 was able to significantly increase the certainty of atomic positions (from 0.83 to 0.26). These numbers should be taken into account when making hypotheses based on distance measurements of the structures.