 |
 |
Dear Jacob, Andrea Thorn and I will be demonstrating such a program (called AnoDe) at the Software Fayre at the IUCr Meeting in Madrid and it is already available from my beta-test site on email request. AnoDe requires only two input files: a PDB file of the refined structure and the name_fa.hkl file from SHELXC that includes the phase shift alpha that is added to the heavy atom phase to get a starting value for the native phase in experimental phasing by SAD, MAD, SIRAS etc. Anode determines the heavy atom substructure phase by subtracting alpha from the native phase that it calculates from the PDB file. The resulting 'heavy atom density' is summarised in a variety of useful ways and a file is written for Coot to display it. The advantage of this extremely simple approach is that it can be used for SAD, SIR, SIRAS, MAD and RIP phase information and that apart from SHELXC no other program, library, environment etc. are required. Best wishes, George On Wed, Jul 06, 2011 at 11:46:14AM -0500, Jacob Keller wrote: > Dear Crystallographers, > > it seems to me that for clearly identifying/characterising anomalous > scatterers for a solved structure, one could make a map using two > datasets: one at the f" peak, one low energy remote. One would then > use the signal both from the Bijvoet differences in the peak dataset > plus the differences between the peak and low-energy datasets, which I > think I have seen called "dispersive" differences. I guess this would > be like a MAD map, but using pre-existing model phases--is there such > an animal in the software, or would it even be helpful? > > Jacob Keller > > -- > ******************************************* > Jacob Pearson Keller > Northwestern University > Medical Scientist Training Program > cel: 773.608.9185 > email: [log in to unmask] > ******************************************* > -- Prof. George M. Sheldrick FRS Dept. Structural Chemistry, University of Goettingen, Tammannstr. 4, D37077 Goettingen, Germany Tel. +49-551-39-3021 or -3068 Fax. +49-551-39-22582