This section covers the Simple Point Charge - Extended (SPC-E) water model parameters as they are implemented into
the towhee_ff_SPC-E file in the ForceFields directory. All of the Towhee atom types for the SPC-E water force
field are listed, along with a short description of their meanings. This is
not really a comphrehensive stand-alone force field, but instead a popular model for water.
Note that these are Lennard-Jones (12-6)
parameters and can only be combined with other Lennard-Jones (12-6) force fields.
Any discrepencies (especially typos) from the published SPC-E force field values
are the sole responsibility of Marcus G. Martin, and I welcome feedback on how this implementation compares
with other programs.
References for SPC-E water
SPC-E in Towhee
The official force field name for Simple Point Charge - Extended water in Towhee is 'SPC-E'. Here I list all of
the SPC-E atom names for use in the towhee_input file, along with a brief description (although
the meaning of the atom names should be obvious).
Please note that the capitalization and spacing pattern is important
and must be followed exactly as listed here.
- 'HW' : hydrogen in water
- 'OW' : oxygen in water
Atom centered point charges are used to represent the electrostatic interactions.
- 'HW' : 0.4238
- 'OW' : -0.8476
This force field only has parameters for water so there are no improper torsions.
This force field only has parameters for water, and while you are welcome to use them with another protein
force field, there are no amino acids in the SPC-E force field.
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