Location of Heavy Atoms by Automated Patterson Interpretation

Abstract

Automated computer interpretation of the Patterson function using superposition techniques provides an effective way of locating heavy atoms in small moiety structures, and — normally from isomorphous or anomalous difference data — also in macromolecules. Another promising approach is to locate potential heavier atoms by random start real/reciprocal space iteration, and then to use the Patterson superposition function as a figure of merit to identify the correct solutions.. Under particularly favorable circumstances, the location of heavier atoms with the help of the Patterson function, combined with automated E-Fourier recycling, provides an ab initio method of solving the phase problem for small proteins from the native data alone, without the use of heavy-atom derivatives, anomalous dispersion, or chemical information in the form of molecular fragments of known geometry.