From: Thomas E. Cheatham <>
Date: Tue 11 May 1999 11:20:48 -0400

Recently we published a modified version of the Cornell et al. (JACS
117, 5316-5340 (1995)) force field for nucleic acids:

  T. E. Cheatham, P. Cieplak & P. A. Kollman. "A modified version of the
  Cornell et al. force field with improved sugar pucker phases and helical
  repeat." J. Biomol. Struct. Dyn. 16, 845-862 (1999).

This force field overcomes some deficiencies in the earlier force field in
the representation of helical twist, sugar pucker and chi (all of which
are a little too low) in B-DNA structures. I had made the parm.dat file
available via anonymous ftp at:

But alas, I put the wrong file there! So, if anyone has grabbed this file
prior to today, they likely have the wrong set of parameters, i.e. not
that described by the JBSD paper cited above but those of a much earlier
revision to the Cornell et al. force field.

My sincere apologies to anyone I've led astray; send me hate mail if you
must. Sorry again.

Thomas Cheatham, III
CBS, LBC, NHLBI, 12A/2041
National Institutes of Health
Bethesda, MD 20892-5626
(301) 402-0617
FAX: (301) 496-2172
Received on Tue May 11 1999 - 08:20:48 PDT
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