Many times when we search for anomalous scatterers, we have some a priori info about their relative positions. For example, many proteins have sequence-adjacent methionines, which tether the anomalous scattering positions to certain distances. Again, there are many heavy atom derivatives which have a known substructure, such as tungsten clusters, or even undecagold clusters. It would seem to me that this kind of a priori info might lend a powerful boost to heavy atom searches in noisy data.
One way I was thinking about to implement this would be to trick a molecular replacement program into searching an anomalous Patterson map for the requisite substructures, but I am not entirely sure about the best way to implement this. My questions are really two: 1. How much extra atom-finding power does one gain by telling the programs the a priori structural information? and 2. What would be the best way to implement this idea in the given software? All the best, Jacob Keller *********************************** Jacob Keller Northwestern University 6541 N. Francisco #3 Chicago IL 60645 (847)467-4049 [EMAIL PROTECTED] ***********************************
