[ccp4bb]: DMMULTI or AMORE

[Andrew Gulick <agulick@facstaff.wisc.edu>]

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Greetings all,

I have a multi-crystal problem and am trying to work through this.
Any suggestions would be greatly appreciated.  I believe DMMULTI
or AMORE can solve this problem but am having trouble figuring
out which is the best way to proceed.

I have 3 selenomet data sets for a hexagonal crystal form.  The
crystal are highly anisotropic and diffract to 2.8 A perpendicular
to the 6-fold, but only ~5A along the 6-fold.  I can get reasonable
completeness (>90%) using data to 3.5A and can solve the substructure
using either SOLVE or SHELX.  The problem is that because
of the anisotropy, the native maps generated from these programs
are ropy and elongated along Z which, together with the
low resolution of the data sets, makes it nearly impossible to build
the model.  It appears that there is only one subunit in the asymmetric
unit for this crystal form.

I also have a native data set for this protein that crystallized in a
second crystal form.  This orthorhombic form has two
subunits in the AU and I have data to 2.1 A.

My question is what is the best way to use the phase information
from the first MAD data to phase the second native form.  It
seems to me that I can use AMORE to generate tabling information
from the hexagonal form F and Phi values.  Or I can use
the multicrystal capabilities of DMMULTI to phase the orthorhombic
form.  What I cannot figure out is if DMMULTI will only
improve/compare phases from two data sets or if this program
will take phases from one crystal form and transfer them to a
second.  In other words, does it work if I have no phase
information for the second crystal form or will it only improve
the (previously obtained) phases from two different forms?

I've found some similar cases in the bulletin board archives but
can't find exactly what information I need.  Thanks again
for any suggestions.

-Andy
--
Andrew M. Gulick                PH   608-262-0742
University of Wisconsin
433 Babcock Dr.  Madison WI 53705