Packet Size - Variable
| IDN | Description |
| 1 | residue name (4 characters) |
| 2 | atom name (4 characters, first part is scattering factor name) |
| 3 | relative back chain bond |
| 4 | relative furthest forward chain bond |
| 5 | group KEY (1=start group; 0=same group as back chain group; |
| -1=no group; -9=dummy atom) | |
| 6 | rotational angle energy value |
| 7 | number of rotational barriers |
| 8 | angle of minimum energy |
| 9 | backward bond length |
| 10 | backward bond angle |
| 11 | backward dihedral angle |
| 12 | energy associated with rotation about bond |
| 13 | energy associated with bond angle distortion |
| 14 | energy associated with dihedral distortion |
| 15 | energy associated with second dihedral distortion |
| 16 | value of second dihedral angle |
| 17 | Lennard-Jones coefficient A |
| 18 | Lennard-Jones coefficient B |
| 19 | Lennard-Jones coefficient C |
| 20 | special position KEY (-3=water oxygen; -2= - charged atom; +2=+charged atom; +1=other polar group; 0=non-polar atom) |