Hi,
I am refining a structure of 2.3A resolution. The R values with and
without bulk solvent and anisotropic scale are quite different as you
can see here:
Start R-work = 0.3751, R-free = 0.5562 (no bulk solvent and anisotropic scale)
Final R-work = 0.3741, R-free = 0.5557 (no bulk solvent and anisotropic scale)
Start R-work = 0.2298, R-free = 0.2974
Final R-work = 0.2261, R-free = 0.2970
I checked the anisotropy of the data with different tools:
Results from Xtriage:
Maximum likelihood isotropic Wilson scaling
ML estimate of overall B value of None:
39.25 A**2
Estimated -log of scale factor of None:
-2.59
Maximum likelihood anisotropic Wilson scaling
ML estimate of overall B_cart value of None:
50.10, 0.00, 0.00
50.10, -0.00
25.47
Equivalent representation as U_cif:
0.63, -0.00, -0.00
0.63, 0.00
0.32
Eigen analyses of B-cart:
Value Vector
Eigenvector 1 : 50.103 ( 0.71, 0.71, -0.00)
Eigenvector 2 : 50.103 (-0.71, 0.71, -0.00)
Eigenvector 3 : 25.473 (-0.00, 0.00, 1.00)
ML estimate of -log of scale factor of None:
-2.57
Correcting for anisotropy in the data
Results from PHASER:
Principal components of anisotropic part of B affecting observed
amplitudes:
eigenB (A^2) direction cosines (orthogonal coordinates)
8.178 0.9961 0.0879 0.0000
8.178 -0.0879 0.9961 0.0000
-16.357 -0.0000 -0.0000 1.0000
Anisotropic deltaB (i.e. range of principal components): 24.535
Results from Ctruncate:
ANISOTROPY CORRECTION (using intensities):
Anisotropic scaling (orthogonal coords):
| -0.2272 -0.0000 -0.0000 |
| -0.0000 -0.2272 0.0000 |
| -0.0000 0.0000 0.4543 |
Anisotropic U scaling (fractional coords):
| -4.451e-05 -5.622e-23 -1.266e-21 |
| -5.622e-23 -4.451e-05 -8.929e-22 |
| -1.266e-21 -8.929e-22 4.717e-06 |
Anisotropic B scaling (fractional coords):
| -3.514e-03 -4.439e-21 -9.995e-20 |
| -4.439e-21 -3.514e-03 -7.050e-20 |
| -9.995e-20 -7.050e-20 3.725e-04 |
Eigenvalues: 0.7728 0.7728 1.4543
Eigenvalue ratios: 0.5314 0.5314 1.0000
Resolution limit in weakest direction = 3.156 A
Now I am not sure about the severeness of anisotropy and the necessary
procedure and would be very pleased if anyone could help. The electron
density maps look okay related to the resolution. Has anyone
experience with the diffraction anisotropy server or ellipsoidal
truncation with data with comparable anisotropy?
Thank you for your help in advance
Ina
Ina Lindemann
Philipps-Universität Marburg
Pharmazeutische Chemie
AG Klebe
Marbacher Weg 6
35032 Marburg
Tel.: 06421/2825908
