Macromolecular applications of<i>SHELX</i>

The SHELX system for small-molecule crystallography dates back to the early 1970s. The current refinement program, SHELXL97, is also useful for high-resolution macromolecular refinement. SHELXC, D and E are more recent additions for experimental phasing using single-wavelength anomalous dispersion (SAD), single isomorphous replacement (SIR), combined SAD and SIR (SIRAS), multi-wavelength anomalous dispersion (MAD) and radiation-damage-induced phasing (RIP) data. They are fast and simple to use, and in favourable cases produce high-quality maps despite very weak initial phase information. Keywords: SHELX; SHELXC; SHELXD; SHELXE; SHELXL; refinement; experimental phasing; substructure solution; density modification; autotracing