Re: [AMBER] Deprotonation of Tyr

From: Marcos Serrou do Amaral <marcossamaral.gmail.com>
Date: Mon, 21 Aug 2017 15:34:52 -0400

Dear Sowmya,
I am not sure how to do that, but I would try:

cpinutil.py -p model_sol.parm7 -igb 2 -o model_sol.cpin -op
model_sol.mod0.parm7 -resnums 95 188 296 426 517 -states 0 0 0 0 0

and then try to change your cpin file:

STATENE=0.000000,-78.199991,-0.845507,0.000000,
TO
STATENE=0.000000,99.99,-99.99,0.000000,

Good luck!

---
Marcos S.A.
On Mon, Aug 21, 2017 at 11:37 AM, Sowmya Indrakumar <soemya.kemi.dtu.dk>
wrote:
> Dear All,
>
> I want to keep certain TYR in the deprotonated state and one LYS
> protonated while performing constpH MD at pH=7.4 and IS= 0.1M
>
> I generated the initial cpin file and a new parameter file using the below
> mentioned command:
>
> cpinutil.py -p model_sol.parm7 -igb 2 -o model_sol.cpin -op
> model_sol.mod0.parm7 -resnums 95 188 426 517 296 -states 1 1 1 1 0
>
>
> This is how my cpin file looks:
>
> &CNSTPH
>  CHRGDAT=-0.4157,0.2719,-0.0014,0.0876,-0.0152,0.0295,0.
> 0295,-0.0011,-0.1906,
>  0.1699,-0.2341,0.1656,0.3226,-0.5579,0.3992,-0.2341,0.1656,-
> 0.1906,0.1699,
>  0.5973,-0.5679,-0.4157,0.2719,-0.0014,0.0876,-0.0858,0.019,
> 0.019,-0.213,-0.103,
>  0.132,-0.498,0.132,0.777,-0.814,0.0,-0.498,0.132,-0.103,0.
> 132,0.5973,-0.5679,
>  -0.3479,0.2747,-0.24,0.1426,-0.0094,0.0362,0.0362,0.0187,0.
> 0103,0.0103,-0.0479,
>  0.0621,0.0621,-0.0143,0.1135,0.1135,-0.3854,0.34,0.34,0.34,
> 0.7341,-0.5894,
>  -0.3479,0.2747,-0.24,0.1426,-0.10961,0.034,0.034,0.06612,0.01041,0.01041,
>  -0.03768,0.01155,0.01155,0.32604,-0.03358,-0.03358,-1.03581,0.0,0.38604,
>  0.38604,0.7341,-0.5894,
>  PROTCNT=0,3,
>  RESNAME='System: Unknown','Residue: TYR 95','Residue: TYR 188',
>  'Residue: LYS 296','Residue: TYR 426','Residue: TYR 517',
>  RESSTATE=1,1,1,1,0,
>  STATEINF(0)%FIRST_ATOM=1415, STATEINF(0)%FIRST_CHARGE=0,
>  STATEINF(0)%FIRST_STATE=0, STATEINF(0)%NUM_ATOMS=21,
> STATEINF(0)%NUM_STATES=2,
>  STATEINF(1)%FIRST_ATOM=2786, STATEINF(1)%FIRST_CHARGE=0,
>  STATEINF(1)%FIRST_STATE=0, STATEINF(1)%NUM_ATOMS=21,
> STATEINF(1)%NUM_STATES=2,
>  STATEINF(2)%FIRST_ATOM=4476, STATEINF(2)%FIRST_CHARGE=42,
>  STATEINF(2)%FIRST_STATE=2, STATEINF(2)%NUM_ATOMS=22,
> STATEINF(2)%NUM_STATES=2,
>  STATEINF(3)%FIRST_ATOM=6410, STATEINF(3)%FIRST_CHARGE=0,
>  STATEINF(3)%FIRST_STATE=0, STATEINF(3)%NUM_ATOMS=21,
> STATEINF(3)%NUM_STATES=2,
>  STATEINF(4)%FIRST_ATOM=7780, STATEINF(4)%FIRST_CHARGE=0,
>  STATEINF(4)%FIRST_STATE=0, STATEINF(4)%NUM_ATOMS=21,
> STATEINF(4)%NUM_STATES=2,
>  STATENE=0.000000,-78.199991,-0.845507,0.000000,
>  TRESCNT=5,CPHFIRST_SOL=10324, CPH_IGB=2, CPH_INTDIEL=1.0,
> /
>
> I manually changed the cpin file " PROTCNT=1,0,3,2," to  PROTCNT="0,3," to
> only consider deprotonated TYR and protonated LYS. Is this the right way?
>
>
> After the equilibration step, *.cpout file looks like this for all time
> steps:
>
> Solvent pH:  7.40000
> Monte Carlo step size:      500
> Time step:      500
> Time:   1000.998
> Residue    0 State:  0
> Residue    1 State:  0
> Residue    2 State:  0
> Residue    3 State:  0
> Residue    4 State:  0
>
> Residue    0 State:  0
> Residue    1 State:  0
> Residue    2 State:  0
> Residue    3 State:  0
> Residue    4 State:  0
>
> Residue    0 State:  0
> Residue    1 State:  0
> Residue    2 State:  0
> Residue    3 State:  0
> Residue    4 State:  0
>
> Residue    0 State:  0
> Residue    1 State:  0
> Residue    2 State:  0
> Residue    3 State:  0
> Residue    4 State:  0
>
> Does the State 0 above mean, the default state which I have mentioned in
> the cpin file??
>
> Ideally, when I take any random frame after equilibration step and
> generate a pdb, I should have the deprotonated TYR 95 atom record. But I
> see the proton present.
>
> ATOM   1415  N   TYR    95      50.406  44.914  56.235  1.00  0.00
>    N
> ATOM   1416  H   TYR    95      50.688  44.636  55.305  1.00  0.00
>    H
> ATOM   1417  CA  TYR    95      51.132  44.350  57.398  1.00  0.00
>    C
> ATOM   1418  HA  TYR    95      50.852  44.846  58.327  1.00  0.00
>    H
> ATOM   1419  CB  TYR    95      50.486  42.938  57.435  1.00  0.00
>    C
> ATOM   1420  HB2 TYR    95      50.764  42.428  58.358  1.00  0.00
>    H
> ATOM   1421  HB3 TYR    95      49.403  43.058  57.460  1.00  0.00
>    H
> ATOM   1422  CG  TYR    95      50.962  41.963  56.336  1.00  0.00
>    C
> ATOM   1423  CD1 TYR    95      52.192  41.330  56.655  1.00  0.00
>    C
> ATOM   1424  HD1 TYR    95      52.737  41.608  57.544  1.00  0.00
>    H
> ATOM   1425  CE1 TYR    95      52.756  40.465  55.709  1.00  0.00
>    C
> ATOM   1426  HE1 TYR    95      53.777  40.165  55.897  1.00  0.00
>    H
> ATOM   1427  CZ  TYR    95      52.155  40.250  54.423  1.00  0.00
>    C
> ATOM   1428  OH  TYR    95      52.880  39.621  53.479  1.00  0.00
>    O
> ATOM   1429  HH  TYR    95      52.243  39.414  52.791  1.00  0.00
>    H
> ATOM   1430  CE2 TYR    95      50.991  40.970  54.148  1.00  0.00
>    C
> ATOM   1431  HE2 TYR    95      50.645  41.009  53.126  1.00  0.00
>    H
> ATOM   1432  CD2 TYR    95      50.363  41.795  55.070  1.00  0.00
>    C
> ATOM   1433  HD2 TYR    95      49.499  42.394  54.825  1.00  0.00
>    H
> ATOM   1434  C   TYR    95      52.628  44.429  57.246  1.00  0.00
>    C
>
> I kindly need you're comments on this.
>
> Thanks
> Regards
> Sowmya
> ________________________________________
> From: Sowmya Indrakumar [soemya.kemi.dtu.dk]
> Sent: Friday, August 18, 2017 5:24 PM
> To: amber.ambermd.org
> Subject: [AMBER] Deprotonation of Tyr
>
> Dear All,
> I wish to perform simulations with varying salt concentration of NaCl of
> upto 200mM at a particular pH=7. I want to keep some of the Tyrosines in
> the deprotonated state.
>
> So here, my question is, Can I perform these simulations using constant pH
> MD? Because, I think concentrations can be adjusted to upto 0.1M.
>
> Is there any other way to consider doing the deprotonation?
> Kindly, give me you're suggestion in this regard.
> Regards
> Sowmya
>
>
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Received on Mon Aug 21 2017 - 13:00:03 PDT
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