The solution of protein structures containing several anomalous scatterers of the same kind

Many proteins contain a number of atoms of the same kind which are potential anomalous scatterers. It is shown that from two data sets, one normal and one with anomalous scattering, it is possible to extract the contribution of the anomalous scatterers and to solve for them by normal direct methods. From the phases of the structure factors of the anomalous scatterers alone the phases of the normal protein structure factors may, in principle, be found exactly.