This server uses software developed by the Phenix project, specifically the phenix.xtriage program, and software developed in our lab.

SAVES | [XdVal] | MTZdump | Ramachandran Plot | pdbU | pdbSNAFU (Check for ADIT compliance) | PROCHECK | Verify3D | ERRAT

L test for acentric data using difference vectors (dh,dk,dl) of the form: (2hp,2kp,2lp) where hp, kp, and lp are random signed integers such that 2 <= |dh| + |dk| + |dl| <= 8 Mean |L| :0.516 (untwinned: 0.500; perfect twin: 0.375) Mean L^2 :0.358 (untwinned: 0.333; perfect twin: 0.200) The distribution of |L| values indicates a twin fraction of 0.00. Note that this estimate is not as reliable as obtained via a Britton plot or H-test if twin laws are available. --------------------------------------------- Analysing possible twin law : l,-k,h --------------------------------------------- Results of the H-test on acentric data: (Only 50.0% of the strongest twin pairs were used) mean |H| : 0.489 (0.50: untwinned; 0.0: 50% twinned) mean H^2 : 0.333 (0.33: untwinned; 0.0: 50% twinned) Estimation of twin fraction via mean |H|: 0.011 Estimation of twin fraction via cum. dist. of H: 0.021 Britton analyses Extrapolation performed on 0.00 < alpha < 0.495 Estimated twin fraction: -0.020 Correlation: 0.9996 R vs R statistic: R_abs_twin = <|I1-I2|>/<|I1+I2|> Lebedev, Vagin, Murshudov. Acta Cryst. (2006). D62, 83-95 R_abs_twin observed data : 0.535 R_sq_twin = <(I1-I2)^2>/<(I1+I2)^2> R_sq_twin observed data : 0.380 No calculated data available. R_twin for calculated data not determined. Maximum Likelihood twin fraction determination Zwart, Read, Grosse-Kunstleve & Adams, to be published. The estimated twin fraction is equal to 0.022 Exploring higher metric symmetry The point group of data as dictated by the space group is P 2 3 The point group in the niggli setting is P 2 3 The point group of the lattice is P 4 3 2 A summary of R values for various possible point groups follow. ---------------------------------------------------------------------------------------------- | Point group | mean R_used | max R_used | mean R_unused | min R_unused | BIC | choice | ---------------------------------------------------------------------------------------------- | P 4 3 2 | 0.535 | 0.535 | None | None | 3.199e+06 | | | P 2 3 | None | None | 0.535 | 0.535 | 6.451e+04 | <--- | ---------------------------------------------------------------------------------------------- R_used: mean and maximum R value for symmetry operators *used* in this point group R_unused: mean and minimum R value for symmetry operators *not used* in this point group An automated point group suggestion is made on the basis of the BIC (Bayesian information criterion). The likely point group of the data is: P 2 3 Possible space groups in this point group are: Unit cell: (150.28, 150.28, 150.28, 90, 90, 90) Space group: P 2 3 (No. 195) Unit cell: (150.28, 150.28, 150.28, 90, 90, 90) Space group: P 21 3 (No. 198) Note that this analysis does not take into account the effects of twinning. If the data are (almost) perfectly twinned, the symmetry will appear to be higher than it actually is. ----------------------------------------------------------------------------------------------------------------- Merging in *highest possible* point group P 4 3 2. ***** THIS MIGHT NOT BE THE BEST POINT GROUP SYMMETRY ***** ----------------------------------------------------------------------------------------------------------------- R-linear = sum(abs(data - mean(data))) / sum(abs(data)) R-square = sum((data - mean(data))**2) / sum(data**2) In these sums single measurements are excluded. Redundancy Mean Mean Min Max Mean R-linear R-square unused: - 9.9965 bin 1: 9.9965 - 6.7635 1 2 1.798 0.5277 0.3309 bin 2: 6.7635 - 5.6778 1 2 1.817 0.5183 0.2808 bin 3: 5.6778 - 5.0653 1 2 1.831 0.5329 0.2896 bin 4: 5.0653 - 4.6532 1 2 1.832 0.5120 0.2668 bin 5: 4.6532 - 4.3491 1 2 1.851 0.5396 0.2915 bin 6: 4.3491 - 4.1115 1 2 1.839 0.5304 0.2787 bin 7: 4.1115 - 3.9186 1 2 1.848 0.5375 0.2778 bin 8: 3.9186 - 3.7575 1 2 1.848 0.5534 0.2905 bin 9: 3.7575 - 3.6199 1 2 1.874 0.5445 0.2777 bin 10: 3.6199 - 3.5006 1 2 1.863 0.5564 0.2849 unused: 3.5006 - Suggesting various space group choices on the basis of systematic absence analyses Analyses of the absences table indicates a number of likely space group candidates, which are listed below. For each space group, the number of absent violations are listed under the '+++' column. The number of present violations (weak reflections) are listed under '---'. The last column is a likelihood based score for the particular space group. Note that enantiomorphic spacegroups will have equal scores. Also, if absences were removed while processing the data, they will be regarded as missing information, rather then as enforcing that absence in the space group choices. ------------------------------------------------------------------------------------ | space group | n absent | |