One of the most lucid explanations of how translational NCS results in peaks in
a self-Patterson map is provided in Phil Evans’ classic paper, “Rotations and
rotation matrices”, which is an Open Access publication. In particular, check
out Figure 4, which illustrates a non-crystallographic dyad
Hello, in the self-rotation function the peaks arising from the NCS rotation
axes are good at hiding under the peaks for the crystallographic rotations,
which is because they are actually translational NCS elements, I think. Also,
sorry Eleanor, a double-check on wikipedia confirms the space
I would look VERY carefully at your data processing. CCP4I2 report is a
good place to start.
The self rotation with the ring around the edge is hard to reconcile with
two molecules in the asymmetric unit.
Are the images clean or streaky? Do you have a photo of the crystal?
And by the way - you
Dear John,
It’s hard to be absolutely certain from the reproduction, but it looks like you
have equally high 2-fold axes all around the xy plane in the self-rotation
function. Do you have an explanation for that?
It would be helpful to know the heights of the Patterson peaks relative to the
