I forgot to say in my email about the program AnoDe that of course it also uses the FA values from the SHELXC output file name_fa.hkl as the amplitudes for the 'heavy atom map' with phases (native-alpha). This procedure is remarkably simple and effective.
George On Thu, Jul 07, 2011 at 09:46:37AM +0200, George M. Sheldrick wrote: > 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: [email protected] > > ******************************************* > > > > -- > 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 > -- 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
