2018 AMBER tutorial with 2nnq
From Rizzo_Lab
2nnq with an explicit solvent model
Prepare the files
Convert 2nnq.lig.withH.charged.mol2 to pdb in chimera
Convert 2nnq.rec.withH.charged.mol2 to pdb in chimera
Copy into zzz.master
Parameters
Move into 000.programs
Paramaterize the ligand
antechamber -i ../zzz.master/2nnq.lig.withH.charged.pdb -fi pdb -o 2nnq_lig.am1bcc.mol2 -fo mol2 -at gaff2 -c bcc -rn LIG -nc 1
Check for missing force field parameters
parmchk2 -i 2nnq_lig.am1bcc.mol2 -f mol2 -o 2nnq_lig.am1bcc.frcmod
TLeap
Move into 001.tleap_build
Create tleap.build.in file
#!/usr/bin/sh
###Load Protein force field
source leaprc.protein.ff14SB
###Load GAFF force field (for our ligand)
source leaprc.gaff
###Load TIP3P (water) force field
source leaprc.water.tip3p
####Load Ions frcmod for the tip3p model
loadamberparams frcmod.ionsjc_tip3p
###Needed so we can use igb=8 model
set default PBradii mbondi3
###Load Protein pdb file
rec=loadpdb ../zzz.master/2nnq.rec.withH.charged.pdb
###Load Ligand frcmod/mol2
loadamberparams ../000.parameters/2nnq_lig.am1bcc.frcmod
lig=loadmol2 ../000.parameters/2nnq_lig.am1bcc.mol2
###Create gas-phase complex
gascomplex= combine {rec lig}
###Write gas-phase pdb
savepdb gascomplex 2nnq.gas.complex.pdb
###Write gas-phase toplogy and coord files for MMGBSA calc
saveamberparm gascomplex 2nnq.gas.complex.prmtop 2nnq.gas.complex.rst7
saveamberparm rec 2nnq.gas.receptor.prmtop 2nnq.gas.receptor.rst7
saveamberparm lig 2nnq.gas.ligand.prmtop 2nnq.gas.ligand.rst7
###Create solvated complex (albeit redundant)
solvcomplex= combine {rec lig}
###Solvate the system
solvateoct solvcomplex TIP3PBOX 12.0
###Neutralize system (it will add either Na or Cl depending on net charge)
addions solvcomplex Cl- 0
addions solvcomplex Na+ 0
###Write solvated pdb file
###Create solvated complex (albeit redundant)
solvcomplex= combine {rec lig}
###Solvate the system
solvateoct solvcomplex TIP3PBOX 12.0
###Neutralize system (it will add either Na or Cl depending on net charge)
addions solvcomplex Cl- 0
addions solvcomplex Na+ 0
###Write solvated pdb file
Create Amber topology and coordinates files for the MD simulation
tleap -f tleap.build.in
Equilibration
Create a submission script to equilibrate the biological system
#!/bin/sh
#PBS -N 2nnq_equilibration
#PBS -l walltime=04:00:00
#PBS -l nodes=2:ppn=28
#PBS -j oe
#PBS -q long
cd $PBS_O_WORKDIR
echo "Started Equilibration on `date` "
do_parallel="sander"
prmtop="../001.tleap_build/2nnq.wet.complex.prmtop"
coords="../001.tleap_build/2nnq.wet.complex"
MDINPUTS=(01.min 02.equil 03.min 04.min 05.min 06.equil 07.equil 08.equil 09.equil)
for input in ${MDINPUTS[@]}; do
$do_parallel -O -i ${input}.mdin -o ${input}.mdout -p $prmtop -c ${coords}.rst7 -ref ${coords}.rst7 -x ${input}.trj -inf
${input}.info -r ${input}.rst7
coords=$input
done
echo "Finished Equilibration on `date` "
Submit the job
qsub md.equilibration.sh
