X-dVal: X-ray Data Validation

phenix.xtriage / Matthew's Coefficient / Twinning Detection / CRYST Record analysis

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


Job 53 (Mar 25th, 2013 [02:09 PM])   → twinning detected

Your X-dVal Results

Back to front page
Section
Summary
Completeness Plot
CRYST1 Record Search
Twin Detection Plot
Anisotropicity analyses
Twinning Analyses
Patterson analyses
Systematic absences
Wilson ratio and moments
L test for acentric data
Twinning and intensity statistics summary
##                   Twinning Analyses                ##
##----------------------------------------------------##



Using data between 10.00 to 3.50 Angstrom.

Determining possible twin laws.

The following twin laws have been found:

-------------------------------------------------------------------------------
| Type | Axis   | R metric (%) | delta (le Page) | delta (Lebedev) | Twin law |
-------------------------------------------------------------------------------
|   M  | 2-fold | 0.000        | 0.000           | 0.000           | l,-k,h   |
-------------------------------------------------------------------------------
M:  Merohedral twin law
PM: Pseudomerohedral twin law

1 merohedral twin operators found
0 pseudo-merohedral twin operators found
In total,   1 twin operator were found


The presence of twin laws indicates the following:
The symmetry of the lattice (unit cell) is higher (has more elements)
than the point group of the assigned space group.

There are four likely scenarios associated with the presence of twin laws:
i.  The assigned space group is incorrect (too low).
ii.  The assigned space group is correct and the data *is not* twinned.
iii.  The assigned space group is correct and the data *is* twinned.
iv.  The assigned space group is not correct (too low) and at the same time, the data *is* twinned.

Xtriage tries to distinguish between these cases by inspecting the intensity statistics.
It never hurts to carefully inspect statistics yourself and make sure that the automated
interpretation is correct.



Details of automated twin law derivation
----------------------------------------
Below, the results of the coset decomposition are given.
Each coset represents a single twin law, and all symmetry equivalent twin laws are given.
For each coset, the operator in (x,y,z) and (h,k,l) notation are given.
The direction of the axis (in fractional coordinates), the type and possible offsets are given as well.
Furthermore, the result of combining a certain coset with the input space group is listed.
This table can be usefull when comparing twin laws generated by xtriage with those listed in lookup tables
In the table subgroup H denotes the *presumed intensity symmetry*. Group G is the symmetry of the lattice.

Left cosets of :
subgroup  H: P 2 3
and group G: P 4 3 2

Coset number :     0   (all operators from H)

x,y,z                 h,k,l   Rotation:    1 ; direction:  (0, 0, 0) ; screw/glide:    (0,0,0)
x,-y,-z               h,-k,-l   Rotation:    2 ; direction:  (1, 0, 0) ; screw/glide:    (0,0,0)
-x,y,-z               -h,k,-l   Rotation:    2 ; direction:  (0, 1, 0) ; screw/glide:    (0,0,0)
-x,-y,z               -h,-k,l   Rotation:    2 ; direction:  (0, 0, 1) ; screw/glide:    (0,0,0)
z,x,y                 k,l,h   Rotation:    3 ; direction:  (1, 1, 1) ; screw/glide:    (0,0,0)
y,z,x                 l,h,k   Rotation:    3 ; direction:  (1, 1, 1) ; screw/glide:    (0,0,0)
-y,-z,x               l,-h,-k   Rotation:    3 ; direction: (1, -1, 1) ; screw/glide:    (0,0,0)
z,-x,-y               -k,-l,h   Rotation:    3 ; direction: (1, -1, 1) ; screw/glide:    (0,0,0)
-y,z,-x               -l,-h,k   Rotation:    3 ; direction: (-1, 1, 1) ; screw/glide:    (0,0,0)
-z,-x,y               -k,l,-h   Rotation:    3 ; direction: (-1, 1, 1) ; screw/glide:    (0,0,0)
-z,x,-y               k,-l,-h   Rotation:    3 ; direction: (-1, -1, 1) ; screw/glide:    (0,0,0)
y,-z,-x               -l,h,-k   Rotation:    3 ; direction: (-1, -1, 1) ; screw/glide:    (0,0,0)

Coset number :     1   (H+coset[1] = P 4 3 2)

z,-y,x                l,-k,h   Rotation:    2 ; direction:  (1, 0, 1) ; screw/glide:    (0,0,0)
-y,-x,-z              -k,-h,-l   Rotation:    2 ; direction: (-1, 1, 0) ; screw/glide:    (0,0,0)
-z,-y,-x              -l,-k,-h   Rotation:    2 ; direction: (-1, 0, 1) ; screw/glide:    (0,0,0)
y,x,-z                k,h,-l   Rotation:    2 ; direction:  (1, 1, 0) ; screw/glide:    (0,0,0)
-x,z,y                -h,l,k   Rotation:    2 ; direction:  (0, 1, 1) ; screw/glide:    (0,0,0)
-x,-z,-y              -h,-l,-k   Rotation:    2 ; direction: (0, -1, 1) ; screw/glide:    (0,0,0)
x,-z,y                h,l,-k   Rotation:    4 ; direction:  (1, 0, 0) ; screw/glide:    (0,0,0)
y,-x,z                -k,h,l   Rotation:    4 ; direction:  (0, 0, 1) ; screw/glide:    (0,0,0)
z,y,-x                -l,k,h   Rotation:    4 ; direction:  (0, 1, 0) ; screw/glide:    (0,0,0)
-y,x,z                k,-h,l   Rotation:    4 ; direction:  (0, 0, 1) ; screw/glide:    (0,0,0)
-z,y,x                l,k,-h   Rotation:    4 ; direction:  (0, 1, 0) ; screw/glide:    (0,0,0)
x,z,-y                h,-l,k   Rotation:    4 ; direction:  (1, 0, 0) ; screw/glide:    (0,0,0)

Note that if group H is centered (C,P,I,F), elements corresponding to centering operators are omitted.
(This is because internally the calculations are done with the symmetry of the reduced cell)






Splitting data in centrics and acentrics
Number of centrics  : 1209
Number of acentrics : 12351