An electron-density map calculated using `SAD best centric' phases. The electron-density map displays higher connectivity and is more easily interpreted than the map calculated using conventional `SAD best' phases. The maps were calculated using data to 1.2 Å resolution and contoured at 1.4σ. The sticks represent the refined coordinates of snow flea antifreeze protein (PDB entry 3bog). The maps are displayed using PyMOL (DeLano, 2002).