Force constants and atom types were hand-assigned, based by analogy to the parm99 force field.
A artificial bond between P and H5T in the 5' guanosine nucleotide was added to prevent distortion of the terminal OH group; this is similar to the artificial H-H bond in water that keeps it rigid.
An accompanying leap script is also available.
These libraries were created by Tim Meyer and David Case. Contact David Case with questions or comments.