Dear colleagues, I would like to poll the community on the prevailing practice of distinguishing between phosphate and sulfate in their structures. Suppose all of the following apply: 1) a well contoured tetrahedral density in your model-phased 2Fo-Fc map in the active site of your kinase or GTPase protein. 2) a significant, say 5*sigma, coincident peak in your model-phased anomalous difference fourier map from data collected at a Cu rotating anode source. 3) The crystal grew in 2M ammonium sulfate. Please post your answers to the list if you feel this question is of general interest.* Thank you for your input. Wolfram Tempel
*If it is not, I apologize to everyone for wasting their valuable time.
