SnB is a computer program based on Shake-and-Bake, a dual-space direct-methods procedure for determining crystal structures from X-ray diffraction data. This program has been used in a routine fashion to solve difficult structures, containing as many as 1000 unique non-H atoms, that could not be solved by traditional reciprocal-space routines based on the tangent formula alone. Recently, SnB has also been used to determine the anomalously scattering substructures of selenomethionyl-substituted proteins containing as many as 160 Se sites. Generally, non-substructure applications require that diffraction data be measured to 1.1Å resolution or higher although some structures having several moderately heavy atoms (e.g. S or Cl) have been solved at 1.4Å. SAS or SIR substructure applications routinely use 3Å data and have been successful at a resolution as low as 5Å.

The current version, SnB v2.3, provides a graphical user interface for (i) computing normalized structure-factor magnitudes, (ii) the main Shake-and-Bake phasing algorithm, and (iii) visualization and molecule-editing facilities. SnB can conveniently be run in parallel on multiple processors for faster throughput. It is available for a variety of UNIX platforms, for PCs running Linux, and for Macintosh G4 and G5 computers. In addition, SnB is also available as part of the protein structure determination package, BnP. The BnP interface couples SnB to appropriate components of the PHASES suite, thereby creating an automated pipeline from intensity data to an unambiguous protein electron-density map.

To learn more about SnB, take the SnB tutorial or get the PDF files for some of the references. To obtain an executable copy of SnB, click DOWNLOAD. To check for any patches to SnB v2.3 click Announcements.