Ab initioprotein phasing: the Patterson deconvolution method inSIR2002

Abstract

An automated Patterson deconvolution technique, based on the minimum superposition function, has been implemented into theSIR2002package, a program for theab initiodetermination of small and large molecules. The procedure, combined with the direct-space phase refinement routines present in theSIR2002program, has been designed to solve proteins diffracting at atomic resolution. The procedure has been validated using a large set of test structures, containing either heavy or intermediate atoms (e.g.P, S and Cl) and with structural complexity up to 1500 non-hydrogen atoms in the asymmetric unit. The success, obtained in a completely automatic way, requires a very short computing time and indicates that Patterson deconvolution techniques are a valid alternative to current direct-methods approaches.