Simulating Crystals with the AMBER - System Setup

--- Jupyter notebook version ---

by Hai Nguyen (06/2016)

Original version: http://ambermd.org/tutorials/advanced/tutorial13/XtalTutor1.html

In [1]:
from IPython.display import IFrame

IFrame(src="view.html", width=550, height=550)
Out[1]:

Requirements

  • You are advanced users

  • You successfully installed AmberTools 16 (or greater)

  • Files

  • Install external library for protein viewer: nglview

    $ amber.conda install nglview==0.5.1 -c ambermd

  • Open this notebook

    $ amber.jupyter notebook crystal_simulation_setup.ipynb

How to run this notebook

  • click on each cell border, hit "Ctrl-Enter"

  • Need help? click "Help --> Notebook Help" at the top of this notebook

  • Notes: I keep the same title as the original tutorial

1. Constructing a lattice: You'll need some more tools for this!

Doc: http://ambermd.org/tutorials/advanced/tutorial13/Tarball.html

Viewing original pdb file

In [2]:
import pytraj as pt, nglview as nv

print(pt.__version__, nv.__version__)

traj = pt.load("c1AHO.pdb")
view = nv.show_pytraj(traj)
view

('1.0.4', '0.5-rc.0')
In [3]:
view.add_licorice('water and not hydrogen')

# use view._clear_repr() to clear all representations

You should expect to see

Constructing the unit cell: Where crystal simulations depart from ordinary MD

Doc: http://ambermd.org/tutorials/advanced/tutorial13/Construction.html

In [4]:
!${AMBERHOME}/bin/UnitCell -p c1AHO.pdb -o x1AHO.pdb 
!${AMBERHOME}/bin/PropPDB -p x1AHO.pdb -o x8_1AHO.pdb -ix 2 -iy 2 -iz 2
In [5]:
traj2 = pt.load("x8_1AHO.pdb")
view2 = nv.show_pytraj(traj2)
view2
In [6]:
view2.add_licorice("water and not hydrogen")

You should expect to see

2. Solvating the unit cell: Filling in the gaps

Doc: http://ambermd.org/tutorials/advanced/tutorial13/Solvation.html

In [7]:
! ${AMBERHOME}/bin/AddToBox -c x1AHO.pdb -a Acetate.pdb -na 7 -o xa1AHO.pdb -P 4143 -RP 3.0 -RW 6.0 -G 0.2 -V 1 
! ${AMBERHOME}/bin/AddToBox -c xa1AHO.pdb -a Ammonium.pdb -na 3 -o xm1AHO.pdb -P 4192 -RP 3.0 -RW 6.0 -G 0.2 -V 1 
! ${AMBERHOME}/bin/AddToBox -c xm1AHO.pdb -a spce.pdb -na 179 -o solv1AHO.pdb -P 4192 -RP 3.0 -RW 3.0 -G 0.2 -V 1 

GetPDB >> Found 4144 atoms in x1AHO.pdb.
GetPDB >> Bracketed 772 residues.

GetPDB >> Found 7 atoms in Acetate.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue       6
AddToBox >> Added 7 residues.
AddToBox >> Done.

GetPDB >> Found 4193 atoms in xa1AHO.pdb.
GetPDB >> Bracketed 779 residues.

GetPDB >> Found 5 atoms in Ammonium.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue       2
AddToBox >> Added 3 residues.
AddToBox >> Done.

GetPDB >> Found 4208 atoms in xm1AHO.pdb.
GetPDB >> Bracketed 782 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue      61
AddToBox >> Added 61 residues.
AddToBox >> Residue goal not achieved.
AddToBox >> Re-attempting with solvent clipping radius   2.7000.
GetPDB >> Found 4391 atoms in solv1AHO.pdb.
GetPDB >> Bracketed 843 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue      16
AddToBox >> Added 16 residues.
AddToBox >> Residue goal not achieved.
AddToBox >> Re-attempting with solvent clipping radius   2.4300.
GetPDB >> Found 4439 atoms in solv1AHO.pdb.
GetPDB >> Bracketed 859 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue      14
AddToBox >> Added 14 residues.
AddToBox >> Residue goal not achieved.
AddToBox >> Re-attempting with solvent clipping radius   2.1870.
GetPDB >> Found 4481 atoms in solv1AHO.pdb.
GetPDB >> Bracketed 873 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue      13
AddToBox >> Added 13 residues.
AddToBox >> Residue goal not achieved.
AddToBox >> Re-attempting with solvent clipping radius   1.9683.
GetPDB >> Found 4520 atoms in solv1AHO.pdb.
GetPDB >> Bracketed 886 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue      17
AddToBox >> Added 17 residues.
AddToBox >> Residue goal not achieved.
AddToBox >> Re-attempting with solvent clipping radius   1.7715.
GetPDB >> Found 4571 atoms in solv1AHO.pdb.
GetPDB >> Bracketed 903 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue      23
AddToBox >> Added 23 residues.
AddToBox >> Residue goal not achieved.
AddToBox >> Re-attempting with solvent clipping radius   1.5943.
GetPDB >> Found 4640 atoms in solv1AHO.pdb.
GetPDB >> Bracketed 926 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue      28
AddToBox >> Added 28 residues.
AddToBox >> Residue goal not achieved.
AddToBox >> Re-attempting with solvent clipping radius   1.4349.
GetPDB >> Found 4724 atoms in solv1AHO.pdb.
GetPDB >> Bracketed 954 residues.

GetPDB >> Found 3 atoms in spce.pdb.
GetPDB >> Bracketed 1 residues.

AddToBox >> Examining residue       6
AddToBox >> Added 7 residues.
AddToBox >> Done.

3. Generating a topology: Working with what we have

Doc: http://ambermd.org/tutorials/advanced/tutorial13/Topology.html

In [8]:
%%file solvate.tleap

source leaprc.ff99SB_spce
loadAmberPrep Acetate.prp
loadAmberPrep Ammonium.prp
ammparms = loadAmberParams Ammonium.frcmod
x = loadPdb "solv1AHO.pdb"
bond x.11.SG x.62.SG
bond x.15.SG x.35.SG
bond x.21.SG x.45.SG
bond x.25.SG x.47.SG
bond x.204.SG x.255.SG
bond x.208.SG x.228.SG
bond x.214.SG x.238.SG
bond x.218.SG x.240.SG
bond x.397.SG x.448.SG
bond x.401.SG x.421.SG
bond x.407.SG x.431.SG
bond x.411.SG x.433.SG
bond x.590.SG x.641.SG
bond x.594.SG x.614.SG
bond x.600.SG x.624.SG
bond x.604.SG x.626.SG
set x box {45.900  40.700  30.100}
set default nocenter on
saveAmberParm x solv1AHO.top solv1AHO.crd
quit

Overwriting solvate.tleap
In [9]:
! tleap -f solvate.tleap > solvate.out
In [10]:
! tail -20 solvate.out

 <ACT 777>:  CB   OA1  CA   OA2 
 <ACT 778>:  CB   OA1  CA   OA2 
 <ACT 779>:  CB   OA1  CA   OA2 
 total 883 improper torsions applied
 7 improper torsions in old prep form
Building H-Bond parameters.
Incorporating Non-Bonded adjustments.
Not Marking per-residue atom chain types.
Marking per-residue atom chain types.
  (Residues lacking connect0/connect1 - 
   these don't have chain types marked:

	res	total affected

	CHID	4
	NVAL	4
	WAT	695
  )
 (no restraints)
	Quit
In [11]:
! ${AMBERHOME}/bin/ChBox -c solv1AHO.crd -o solv1AHO.crd -X 45.9 -Y 40.7 -Z 30.1 -al 90.0 -bt 90.0 -gm 90.0
In [12]:
traj3 = pt.load("solv1AHO.crd", "solv1AHO.top")
view3 = nv.show_pytraj(traj3)
view3
In [13]:
view3.add_licorice('water and not hydrogen')

you should expect too see

In [14]:
# check the unitcells
traj3.unitcells
Out[14]:
array([[ 45.9,  40.7,  30.1,  90. ,  90. ,  90. ]])