[AMBER] Problems with minimization energy NaN

From: Bhattacharjee, Sinjini via AMBER <amber.ambermd.org>
Date: Fri, 2 Jun 2023 14:26:43 +0000

Hi, I am trying to minimise a protein-membrane system using sander and pmemd in Amber20. However, the calculation keep crashing in the first cycle with the following error:


NSTEP ENERGY RMS GMAX NAME NUMBER
      1 NaN NaN 1.0669E+24 C19 90066

 BOND = 31692.7352 ANGLE = 68711.0955 DIHED = 59597.8979
 VDWAALS = NaN EEL = -12389.2862 HBOND = 0.0000
 1-4 VDW = NaN 1-4 EEL = -149672.0786 RESTRAINT = 0.0000



This is my initial input:

Minimize
 System minimization:
&cntrl
   imin=1, ntmin=1, nmropt=0
   maxcyc=2000, ncyc=1000,
   ntx=1, irest=0,
   ntpr=100, ntwr=100, iwrap=0,
   ntf=1, ntb=1, cut=10.0, nsnb=20,
   igb=0,
   ibelly=0, ntr=1,
   restraintmask=“.CA", restraint_wt=20.0,
&end
 /


I added the membrane using packmol-memgen.
The system size is huge and I checked and removed clashes in the protein and the non-standard residues.
Can you please tell me what is the problem and how can I solve this? Is it an issue with the parameters or the structure?


Many thanks,

Sinjini Bhattacharjee

PhD Student
Molecular Theory and Spectroscopy
Max-Planck-Institut für Kohlenforschung
45470 Mülheim an der Ruhr, Germany

email: bhattacharjee.kofo.mpg.de<mailto:bhattacharjee.kofo.mpg.de>
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Received on Fri Jun 02 2023 - 07:30:02 PDT
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