12.3.4 Conformations File

The conformations file, which is written by the Write Degree of Freedom (see Write Degree of Freedom), stores the list of conformations generated by the CONGEN command. This file is read and written by subroutines in the file, CGS:CGIO.FLX. The file is unformatted, has a typical extension of .CG, and has the following format:

     HDR,ICNTRL(20)     ! ICNTRL(1)=NRES, ICNTRL(2)=NATOM, ICNTRL(3)=NCONS
     NTITLE,TITLE
     IBASE              ! Taken from PSF
     RES                ! Taken from PSF
     TYPE               ! Taken from PSF
     CONSP              ! List of atoms constructed.
     ! The following record is repeated for each conformation plus one more
     ! at the beginning of the file for the initial coordinates.
     NTITL,((TITLE(I,J),I=1,10),J=1,MIN(10,NTITL)),
           (X(CONSP(I)),Y(CONSP(I)),Z(CONSP(I)),I=1,NCONS),TOTE

The first six records in the file provide enough information to restore coordinates from a conformation in a structure, and they also allow the program, CMPLOOP, see Support Programs for Conformational Search, to differentiate between backbone and sidechains. The title record is taken from the title specified after the CONGEN command.

The remaining records hold conformations. The first conformation stored is not a real conformation, rather it is the coordinates of the constructed atoms prior to the beginning of the search, the so-called reference set. The variable, TOTE, stores the value returned by the last EVL degree of freedom (see Evl Degree of Freedom), or if no EVL was executed, then the total energy for the sidechains as determined in the Sidechain Degree of Freedom, (see Sidechain Degree of Freedom), or 0.0 otherwise.