Dear Amber community,
I applyed the mm_pbsa.pl script to determine the binding free energy o a ligand
to a protein. My statistics.out file shows the following:
#                  COMPLEX                RECEPTOR                  LIGAND
#          ----------------------- -----------------------
-----------------------
#                  MEAN        STD         MEAN        STD         MEAN       
STD
#          ======================= =======================
=======================
ELE            -5303.15    5519.36     -5155.80    5535.87      -136.49     
54.45
VDW            -2632.54       0.00     -2602.06       0.00   3789742.36
12298842.54
INT         49573990.99 8657606.35  49456164.03 8679472.59    117868.77 
287132.38
GAS         49566055.30 8658148.78  49448406.17 8679936.88   3907474.64
12302734.61
PBSUR            169.35       8.90       169.16       8.64         2.75      
0.29
PBCAL         -15530.45    2187.51    -15500.38    2171.48       -65.88     
23.29
PBSOL         -15361.11    2187.01    -15331.21    2171.10       -63.13     
23.22
PBELE         -20833.60    5366.67    -20656.18    5341.50      -202.37     
54.81
PBTOT       49550694.19 8657701.57  49433074.95 8679489.35   3907411.51
12302734.03
GBSUR            243.86      12.82       243.60      12.44         3.96      
0.41
GB            -17701.21    1411.59    -17683.36    1406.15       -69.60     
26.15
GBSOL         -17457.35    1405.56    -17439.76    1400.41       -65.64     
26.06
GBELE         -23004.36    5678.48    -22839.16    5681.10      -206.09     
55.32
GBTOT       49548597.95 8657432.67  49430966.41 8679215.96   3907408.99
12302735.31
#                    DELTA
#          -----------------------
#                  MEAN        STD
#          =======================
ELE              -10.86      79.84
VDW         -3789772.84 12298842.54
INT              -41.81     373.08
GAS         -3789825.50 12298813.02
PBSUR             -2.57       0.78
PBCAL             35.80     213.86
PBSOL             33.24     213.81
PBELE             24.95     222.28
PBTOT       -3789792.27 12298821.27
GBSUR             -3.70       1.12
GB                51.75      50.11
GBSOL             48.06      49.49
GBELE             40.90      78.04
GBTOT       -3789777.45 12298812.93
Analyzing these results I was very stranged by the quite large values of the VDW
and GAS components and the corresponding SD. During the calculation the
following warning messages appeared:
vertex atom mismatch
       atom: 1398
vertex atom: 1395
molsurf: molsurf.c:1055: is_buried: Assertion `sarg1 >= 0.0' failed.
vertex atom mismatch
       atom: 2429
vertex atom: 2428
vertex atom mismatch
       atom: 2798
vertex atom: 2795
vertex atom mismatch
       atom: 2998
vertex atom: 2995
vertex atom mismatch
       atom: 3098
vertex atom: 3095
No skew or curtosis when zero variance in moment
No skew or curtosis when zero variance in moment
No skew or curtosis when zero variance in moment
No skew or curtosis when zero variance in moment
No skew or curtosis when zero variance in moment
No skew or curtosis when zero variance in moment
I run the MD simulation in explicit solvent, and I stripped the waters and
counter ion previous to the mm_pbsa analysis. I also created new prmtop files
of the complex, the receptor and ligand without waters for mm_pbsa.
Any hint about what's going wrong with my system or why these large values 
appears would be greatly appreciated,
Thanks
Alfredo Quevedo
Facultad de Ciencias Químicas
Universidad Nacional de Córdoba
Argentina
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Received on Sun May 14 2006 - 06:07:17 PDT