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Hello, I wanted to make an anomalous difference fourier map of a structure with zinc bound to it. However I have not been successful in making the map and I would really appreciate your help if anyone could suggest me where I am going wrong. I solved this zinc bound structure, by molecular replacement from a calcium bound structure (1.4 angstrom) that I solved. I want to show that the zinc binds to the identical site by the anomalous difference fourier map. I am using CCP4i and the steps that I have been taking are, (names of the files are arbitrary) 1) generating structure factors and phases from the solved coordinates by SFALL Input files zinc bound pdb original zinc .mtz data from synchrotron output file XXXXsfall.mtz 2)merging the XXXXsfall.mtz containing the PHICalc and FCalc columns with the original synchrotron .mtz file containing DANO and SIGDANO by running CAD. input files XXXXsfall.mtz and zinc synchrtron .mtz output file CAD.mtz 3) Running FFT to make anomalous map, selecting labels from CAD.mtz as input files. There is an output map file but nothing in it. all the values are 0 and the map is not recognized by coot. There is no error message in the log file. I must be missing something or doing something wrong/stupid. Thanks, Ivan