MCCCS Towhee (SPC-E water)



    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
Coulombic interactions
    Atom centered point charges are used to represent the electrostatic interactions.
    • 'HW' : 0.4238
    • 'OW' : -0.8476
Improper torsions
    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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Send comments to: Marcus G. Martin
Last updated: September 07, 2005