[AMBER] Some questions about mmpbsa.py

From: 龚乾坤 <m201770109.hust.edu.cn>
Date: Thu, 13 Sep 2018 15:01:12 +0800 (GMT+08:00)

Dear amber developer,

   I have used MMPBSA.PY to calculate entropy, but there are some process I don't understand. The mmpbsa.in file as following:

&general
  verbose=1, keep_files=2, use_sander=1,
  startfram=2001, endframe=2006, interval=5,
/
...
/
&nmode
   nmstartframe=1,
   nmendframe=2,
   nminterval=1,
   dielc=1.0,
   drms=0.001,
   maxcyc=10000,
   nmode_igb=1,
   nmode_istrng=0.0,
/

The process file pbsa.log as following:

....
2 frames were processed by cpptraj for use in calculation.
2 frames were processed by cpptraj for nmode calculations.

Running calculations on normal system...

Beginning PB calculations with /home/haomiao/md/amber16/bin/sander
  calculating complex contribution...
  calculating receptor contribution...
  calculating ligand contribution...

Beginning nmode calculations with /home/haomiao/md/amber16/bin/mmpbsa_py_nabnmode
  calculating complex contribution...
Line minimizer aborted: step at upper bound 0.070443205
Line minimizer aborted: step at upper bound 0.00067657615
Line minimizer aborted: step at upper bound 0.0004082432
Line minimizer aborted: step at upper bound 0.011483969
Line minimizer aborted: step at upper bound 0.011409417
Line minimizer aborted: step at upper bound 0.046362475
Line minimizer aborted: step at upper bound 0.0001097595
  calculating receptor contribution...
Line minimizer aborted: step at upper bound 0.0023964902
Line minimizer aborted: step at upper bound 0.050352631
Line minimizer aborted: step at upper bound 0.0015487836
  calculating ligand contribution...
Line minimizer aborted: step at upper bound 0.086856859
Line minimizer aborted: step at upper bound 9.4704377e-05
Line minimizer aborted: step at upper bound 0.0017161722
Line minimizer aborted: step at upper bound 0.0054606726

Timing:
Total setup time: 0.002 min.
Creating trajectories with cpptraj: 0.015 min.
Total calculation time: 5.222 min.

....

I want to know the mean about "Line minimizer aborted: step at upper bound 0.0054606726" ,and how to deal with it?

and the outputfiel final-result-mmpbsa.dat as following:

 ......

MMPBSA.py Version=14.0
|Solvated complex topology file: charge_prmtop
|Complex topology file: pbsa_com_prmtop
|Receptor topology file: pbsa_rec_prmtop
|Ligand topology file: pbsa_lig_prmtop
|Initial mdcrd(s): 03_Prod_1.mdcrd.1
|
|Receptor mask: ":1-51"
|Ligand mask: ":52-102"
|
|Calculations performed using 2.0 complex frames.
|NMODE calculations performed using 2.0 frames.
|Poisson Boltzmann calculations performed using internal PBSA solver in sander.
|
|All units are reported in kcal/mole.
|All entropy results have units kcal/mol (Temperature is 298.15 K).
....


In my simulation, the temperture is 300K, why the calculation temperature is 298.15K? And how to compute entropy under 300K?




Thanks.

Qiankun
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Received on Thu Sep 13 2018 - 00:30:02 PDT
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