Hi Charles,

This clears up the problem with the geometric energy terms in the 
refine_full.inp calculation.  The resulting energies are:

REMARK FILENAME="test_full_nocoup_1.sa"
REMARK ===============================================================
REMARK            
overall,bonds,angles,improper,vdw,noe,cdih,dipo,rama,ncs,orie,plan,coup,dcsa
REMARK energies: 7463.83, 56.7333, 624.665, 23.0412, 76.5582, 107.253, 0, 
8008.66, -1346.55, 306.293, -944.449, 17.5586,103.479,

compared to the following energies generated using the psf file generated with 
nucleic.top/par:

REMARK FILENAME="test_full_nocoup_1.sa"
REMARK ===============================================================
REMARK            
overall,bonds,angles,improper,vdw,noe,cdih,dipo,rama,ncs,orie,plan,coup,dcsa
REMARK energies: 37050.2, 2329.45, 9680.19, 15715.1, 915.524, 822.767, 
0.241548, 7967.06, -1315.5, 1283.43, -777.791, 4.82553,,

However, although the geometric energy terms are also much lower in the 
refine_full.py calculation, i.e.,

REMARK  ------------------------------------------------------------
REMARK  summary    Name       Energy      RMS     Violations
REMARK  summary total         3987.60               877
REMARK  summary ANGL           924.26    2.028      328
REMARK  summary BOND           215.03    0.016       19
REMARK  summary CDIH            22.36    1.668        4
REMARK  summary IMPR            41.09    0.717        8
REMARK  summary NCS            280.46
REMARK  summary ORIE          -598.45
REMARK  summary PLAN            39.36 ,

compared to the nucleic.top/par calculation, i.e.,

REMARK  ------------------------------------------------------------
REMARK  summary    Name       Energy      RMS     Violations
REMARK  summary total        77782.66               785
REMARK  summary ANGL           934.87    2.039      295
REMARK  summary BOND           252.82    0.018       23
REMARK  summary CDIH            21.94    1.652        2
REMARK  summary IMPR         76386.18   28.835       46
REMARK  summary NCS            651.75
REMARK  summary ORIE          -854.54
REMARK  summary PLAN             7.04  ,

The number of experimental violations is still quite large, and the G24-C1 and 
G12-C13 base interactions are still distorted.

Eugene

Eugene DeRose, Ph.D.
NIEHS NMR Laboratory Manager
Global Health Sector
SRA International, Inc.
Contractor to NIEHS/DIR
National Institute of Environmental Health Sciences
Research Triangle Park, NC 27709
919.541.1981 voice
919.541.5707 fax
derose at niehs.nih.gov
www.niehs.nih.gov
www.sra.com
Enhancing Human Health Around the World Everyday
--







On 2/12/10 4:32 PM, "Charles at Schwieters.org" <Charles at Schwieters.org> 
wrote:

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Hello again Eugene--

> I am trying to use the dna_refi.inp script to compute the structure of the
> Dickerson dodecamer with some ribose sugar substitutions.  Unfortunately the
> structures, especially the base geometries are significantly distorted.
>

I think the issue is indeed a topology file mismatch. In
refine_full.inp, please replace nucleic.top/par with
nucleic-1.0.top/par, and do this to refine_full.py: add these lines:

protocol.topology['nucleic'] = "nucleic-1.0.top"
protocol.parameters['nucleic'] = "nucleic-1.0.par"

before the protocol.initParams line. I previously made this change to
ensemble.py, but forgot to update the other files.

The starting structure is not consistent with the current
topology/parameters. Please let me know if this clears things up.

best regards--
Charles
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