Input
Protein structures in PDB format, and a probe radius.
Searching
Users can either search for pre-computed result by 4-letter PDB ID, or upload their own PDB file for customized computation. The core algorithm helps in finding the pocket or cavity with capability of housing a solvent, with a default or adjusted diameter.
Output
CASTp identifies all surface pockets, interior cavities and cross channels, provides detailed delineation of all atoms participating in their formation, including the area and volume of pocket or void as well as measurement of numbers of mouth opening of a particular pocket ID by solvent accessible surface model (Richards' surface) and by molecular surface model (Connolly surface), all calculated analytically. The core algorithm helps in finding the pocket or cavity with capability  of housing a solvent with a diameter of 1.4 Å. This online tool also supports PyMOL and UCSF Chimera plugin for molecular visualization.