DS 2020: hidden gems (2)

For me, another hidden gem in the Discovery Studio 2020 Product Release Document is DSC-26037, where you can now read in CRD and PSF files created by CHARMm calculations and the client will retain all the bond and forcefield information for the molecule. The CHARMm program uses a CRD file to record the atom coordinates of a molecular system and the corresponding PSF file to give the forcefield atom types, partial charges and bonding information. CHARMm uses these files in combination to provide all the information needed to calculate the energy of the system.
With Discovery Studio 2020 you can now read in the CRD or corresponding PSF file from your CHARMm calculation and the Discovery studio client will construct the fully typed molecule ready to perform further calculations. The CRD and PSF files should be located in the same folder and have the same filename prefix. The only step needed prior to reading in the files is to add a line to the header of the PSF file to specify the forcefield. This line should begin with an asterisk followed by the name of the forcefield e.g.

*charmm36

If the forcefield name is not included in the header the default CHARMm forcefield will be assumed.