[AMBER] Thermodynamic Intergration problem

From: Xiaohui Jiang [Contractor] <xjiang.bioanalysis.org>
Date: Wed, 4 Mar 2009 10:36:14 -0500

Hi,

I am using TI with soft-core to study relative binding free energy. I followed the tutorial and tested several additional cases with T4 lysozyme by making small changes in the ligand. Everything went well.

Problem happened when I tried to "mutant" a protein residue (V111T) with the same ligand (benzene). The "charge off" and "charge on" parts have no problem since the v0 and v1 are still the "same" complex and only the charges are changing. The "vdw" part with soft-core caused problem. In the initial minimization step (SD with only 2 processors), the "sander.MPI" process hangs without producing any results. Both processes did not crash, just running without updating output files or producing the "mdinfo" file. I put the two output files in attachments.

The command I started the run was:

openmpirun_wrapper sander.MPI -ng 2 -groupfile group_mini_L0.5

"groupfile group_mini_L0.5" contains:
-O -i VDW_mdin_mini_v0_L0.5 -o VDW_mdout_mini_v0_L0.5 -p T4_comp.prm -c T4_comp.rst -r T4_comp_mini_v0_0.5.rst
-O -i VDW_mdin_mini_v1_L0.5 -o VDW_mdout_mini_v1_L0.5 -p T4_V111T_comp.prm -c T4_V111T_comp.rst -r T4_V111T_comp_mini_v1_0.5.rst

The difference in the two input parameter/coordinate files are only at the residue 111. The ligand, water and counter ions remain the same. The following are the difference in pdb format. Of course the atom numbering is different after residue 111.

"original"
ATOM 1736 N VAL 111 -6.428 0.036 -6.083 1.00 0.00
ATOM 1737 H VAL 111 -6.147 -0.063 -5.118 1.00 0.00
ATOM 1738 CA VAL 111 -6.477 -1.161 -6.915 1.00 0.00
ATOM 1739 HA VAL 111 -5.773 -1.044 -7.739 1.00 0.00
ATOM 1740 CB VAL 111 -6.057 -2.343 -6.088 1.00 0.00
ATOM 1741 HB VAL 111 -6.796 -2.538 -5.310 1.00 0.00
ATOM 1742 CG1 VAL 111 -5.954 -3.559 -7.009 1.00 0.00
ATOM 1743 1HG1 VAL 111 -5.215 -3.365 -7.786 1.00 0.00
ATOM 1744 2HG1 VAL 111 -5.650 -4.430 -6.429 1.00 0.00
ATOM 1745 3HG1 VAL 111 -6.924 -3.750 -7.469 1.00 0.00
ATOM 1746 CG2 VAL 111 -4.691 -2.036 -5.519 1.00 0.00
ATOM 1747 1HG2 VAL 111 -4.748 -1.140 -4.901 1.00 0.00
ATOM 1748 2HG2 VAL 111 -4.354 -2.875 -4.911 1.00 0.00
ATOM 1749 3HG2 VAL 111 -3.986 -1.871 -6.334 1.00 0.00
ATOM 1750 C VAL 111 -7.821 -1.439 -7.544 1.00 0.00
ATOM 1751 O VAL 111 -7.926 -1.788 -8.734 1.00 0.00

"V111T"
ATOM 1736 N THR 111 -6.428 0.036 -6.083 1.00 0.00
ATOM 1737 H THR 111 -6.147 -0.063 -5.118 1.00 0.00
ATOM 1738 CA THR 111 -6.477 -1.161 -6.915 1.00 0.00
ATOM 1739 HA THR 111 -5.773 -1.044 -7.739 1.00 0.00
ATOM 1740 CB THR 111 -6.057 -2.343 -6.088 1.00 0.00
ATOM 1741 HB THR 111 -5.819 -2.008 -5.078 1.00 0.00
ATOM 1742 CG2 THR 111 -7.209 -3.362 -6.026 1.00 0.00
ATOM 1743 1HG2 THR 111 -6.905 -4.219 -5.426 1.00 0.00
ATOM 1744 2HG2 THR 111 -7.456 -3.694 -7.034 1.00 0.00
ATOM 1745 3HG2 THR 111 -8.084 -2.895 -5.573 1.00 0.00
ATOM 1746 OG1 THR 111 -4.900 -2.956 -6.667 1.00 0.00
ATOM 1747 1HG THR 111 -5.124 -3.277 -7.641 1.00 0.00
ATOM 1748 C THR 111 -7.821 -1.439 -7.544 1.00 0.00
ATOM 1749 O THR 111 -7.926 -1.788 -8.734 1.00 0.00

I tried to run this with different memory setup 1.75Gb or 3.5Gb. There is no difference. Also, I tried to bypass minimization and started MD directly. Similar problem encountered. The "sander.MPI" tested was rebuilt on Feb 24, 2009 with latest patches.

 I can provide the files to run the jobs if someone would like to take a look at the problem.

Thanks in advance!

Regards,

Jeff

Xiaohui (Jeff) Jiang, Ph.D.
Research Scientist
Phone: (301) 619-1986
Fax: (301) 619-1983

DoD Biotechnology HPC Software Applications Institute
BHSAI/MRMC, ATTN: MCMR-TT
Building 363 Miller Drive
Fort Detrick, MD 21702-5012


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Received on Fri Mar 06 2009 - 01:10:55 PST
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