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 have noticed that the sample refine_full.inp script generates a good
structure for the sample DNA calculation in eginput/dna_refi as long as the
psf file provided, dna_new.psf, is used, i.e.,

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: 7430.46, 56.3133, 593.507, 10.1168, 76.1481, 114.733, 0,
8004.42, -1340.35, 306.109, -946.373, 17.2073,106.849,

However, if a new structure file is generated using eginput/dna/dna.inp the
geometric energy terms increase dramatically and the base geometry is
significantly distorted, i.e.,

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,

The use of this psf file in the sample eginput/dna/full_ring_03.inp
calculation also results in high energies:

REMARK FILENAME="full_ring_03_1.sa"
REMARK ===============================================================
REMARK    overall,bonds,angles,improper,vdw,noe,cdih,xdip,rama,ncs,orie,plan
REMARK energies: 31243, 2993.69, 9027.05, 18832.2, 398.815, 653.736,
5.06793, 1587.24, -3273.41, 1713.71, -704.531, 9.39292

Upon comparison of the dna_new.psf file provided and the newly created psf
file, I noticed that the new file has more improper terms defined.

As a side note, the sample refine_full.py calculation also produces high
energies with a significant number of experimental violations:

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
REMARK  summary RAMA         -1267.03
REMARK  summary VDW             57.52                 2
REMARK  summary csa             43.94    2.235       44
REMARK  summary jcoup            5.63    0.160       22
REMARK  summary noe             53.87    0.053        0
REMARK  summary rdcs          1488.67    0.537      351

Any suggestions on what might be causing the problem with the psf files will
be greatly appreciated.

Thanks,
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
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