Cross-Rotation Function with the Modified Fab Structure

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Cross-Rotation Function with the Modified Fab Structure

The next step is a cross-rotation function with the modified Fab structure. The model Patterson map P1 is computed by placing the search model into a $120 \times 120 \times 150$ Å orthorhombic box, with the largest extent of the model approximately parallel to the

-direction, and evaluating the structure factors and FFT of the squared amplitudes. Note that all crystallographic symmetry operators of the space group have to be specified without the translational part.

rotation.inp

X-PLOR produced the following list of highest rotation function peaks:

 ! index, theta1, theta2, theta3, RF-function (EPSIlon= 0.25)
      1    14.843  70.000 256.306    4.7813
      2    14.460  70.000  75.923    4.7643
      5    20.250  77.500  92.250    4.6747
      6     3.549  67.500 260.049    4.6676
      8    74.504  82.500 262.163    4.6273
      9     3.173  67.500  79.673    4.6189
     10    20.419  80.000 270.854    4.6173
 ...

You may notice that the first two peaks are related by non-crystallographic symmetry. However, this is only a necessary but not a sufficient condition for the correctness of the solution. In fact, this “solution" is totally wrong.

Xplor-NIH 2025-03-21