SIR2004:: an improved tool for crystal structure determination and refinement

SIR2004 is the evolution of the SIR2002 program [Burla, Camalli, Carrozzini, Cascarano, Giacovazzo, Polidori & Spagna ( 2003). J. Appl. Cryst. 36, 1103]. It is devoted to the solution of crystal structures by direct and Patterson methods. Several new features implemented in SIR2004 make this program efficient: it is able to solve ab initio both small/medium-size structures as well as macromolecules ( up to 2000 atoms in the asymmetric unit). In favourable circumstances, the program is also able to solve protein structures with data resolution up to 1.4 - 1.5 angstrom, and to provide interpretable electron density maps. A powerful user-friendly graphical interface is provided.