[phenixbb] translation/rotation matrix

[Edward A. Berry]

Yogesh Gupta wrote:
> Dear PhenixBB members,
>
> I calculated two maps one using 3 wavelengths Se to 4.2A, and 3
> wavelength Ta to ~3.9A for ~100kDa protein in space group P62 with 1
> molecule in A.U. These crystals are non-isomorphous. Ta MAD map is
> better than Se MAD map. There is no model available at this point. Is
> there a way to transform Se sites accurately to the Ta map?
>

The IMP function of the MAVE program of the uppsala software
factories RAVE package can determine the RT operator relating two
maps given an aproximation for starting point. You could start
with the identity operator with large step size, if the crystals
are somewhat similar.

There is also a 6D search function which might be more practical
now that computers are getting fast, but maybe it is only for
intra-crystal NCS.

You might want to mask out the heavy atom artifacts in the map
being rotated so an artifactual peak doesn't glomm onto the
highest density in the target map and prevent finding the
correct solution.


http://xray.bmc.uu.se/usf/mave_man.html#H10

eab