[gmx-users] Hydroxyapatite MD odd behavior

Ramon Garduno ramon at fis.unam.mx
Sat Jul 28 02:54:18 CEST 2012


Dear Justin,

Thanks for your quick reply. Actually, we think that the topology is OK,
however HAP's parameters could be wrong, we are checking on this...

These are the topology files used for HAP. The names associated to the atoms
present on the slab are:

ACa - Ca2+
AP   -  P
AO1 - O(P)
AO4 - O(H)
AH   - H

1- ffnonbonded.itp
[ atomtypes ]
;name  at.num   mass      charge  ptype       c6           c12
  ACa          40.0800     0.000     A  7.34375e-05   4.755341e-08
   AP          30.9738     0.000     A  1.6701174e-03 2.9953696e-06
  AO1          15.9994     0.000     A  1.8737825e-04 1.4573462e-07
  AO4          15.9994     0.000     A  9.793663e-05  8.5730467e-08
   AH          1.00800     0.000     A  7.17e-11      5.497e-16

[ nonbond_params ]
;      i       j   func     c6           c12
     ACa      ACa  1  7.34375e-05   4.755341e-08
     ACa      AO4  1  8.480696e-05  6.38496e-08
     ACa       AH  1  7.2564e-08    5.112734e-12
     ACa      AO1  1  1.173055e-04  8.324769e-08
     ACa       AP  1  3.50213e-04   3.77223e-07
     AO4      AO4  1  1.8737825e-04 8.5730467e-08
     AO4       AH  1  8.37977e-08   6.864841e-12
     AO4      AO1  1  1.354666e-04  1.117761e-07
     AO4       AP  1  1.2789279e-03 5.0674888e-07
      AH       AH  1  7.17e-11      5.497e-16
      AH      AO1  1  1.159095e-07  8.950437e-12
      AH       AP  1  3.460454e-07  4.057776e-11
     AO1      AO1  1  1.8737825e-04 1.4573462e-07
     AO1       AP  1  5.594137e-04  6.607035e-07
      AP       AP  1  1.6701174e-03 2.9953696e-06

2- HAP-MODEL4-100.itp
;; topology file for a HAP, created by Eduardo Villarreal & Ramon Garduno
;; from hap.itp taken from diferente papers
;; one can use Gromacs force-field files (ffgmx*.itp)
;; If you use this topology file, please cite to Eduardo Villarreal & Ramon
Garduno
;;

[ moleculetype ]
; Name   nrexcl
HAP      3

[ atoms ]
;aqui se hace coincidir cada atomo en la celda de unidad
;   id    atype   resnr resane    aname   cgnr        charge      mass
     1      AO1      1    HAP      O3A       1        -1.4000   15.9994     
     2      AO1      1    HAP      O3B       2        -1.4000   15.9994     
     3      AO1      1    HAP      O3C       3        -1.4000   15.9994     
     4      AO1      1    HAP      O3D       4        -1.4000   15.9994     
     5      AO1      1    HAP      O3E       5        -1.4000   15.9994     
     6      AO1      1    HAP      O3F       6        -1.4000   15.9994     
     7      AO1      1    HAP      O3G       7        -1.4000   15.9994     
     8      AO1      1    HAP      O3H       8        -1.4000   15.9994     
     9      AO1      1    HAP      O3I       9        -1.4000   15.9994     
    10      AO1      1    HAP      O3J      10        -1.4000   15.9994     
    11      AO1      1    HAP      O3K      11        -1.4000   15.9994     
    12      AO1      1    HAP      O3L      12        -1.4000   15.9994     
    13      AO1      1    HAP      O3M       7        -1.4000   15.9994     
    14      AO1      1    HAP      O3N       8        -1.4000   15.9994     
    15      AO1      1    HAP      O3O       9        -1.4000   15.9994     
    16      AO1      1    HAP      O3P      10        -1.4000   15.9994     
    17      AO1      1    HAP      O3Q      11        -1.4000   15.9994     
    18      AO1      1    HAP      O3R      12        -1.4000   15.9994     
    19      AO1      1    HAP      O3S       1        -1.4000   15.9994     
    20      AO1      1    HAP      O3T       2        -1.4000   15.9994   
    21      AO1      1    HAP      O3U       3        -1.4000   15.9994     
    22      AO1      1    HAP      O3V       4        -1.4000   15.9994     
    23      AO1      1    HAP      O3W       5        -1.4000   15.9994     
    24      AO1      1    HAP      O3X       6        -1.4000   15.9994     
    25      AO1      1    HAP      O1A       1        -1.4000   15.9994     
    26      AO1      1    HAP      O1B       2        -1.4000   15.9994     
    27      AO1      1    HAP      O2A       1        -1.4000   15.9994     
    28      AO1      1    HAP      O2B       2        -1.4000   15.9994
    29       AP      1    HAP      P1A       1         2.6000   30.9738
    30       AP      1    HAP      P1B       2         2.6000   30.9738   
    31      ACa      1    HAP      CaA      17         2.0000   40.0800
    32      ACa      1    HAP      CaB      18         2.0000   40.0800
    33      AO1      1    HAP      O1C       3        -1.4000   15.9994     
    34      AO1      1    HAP      O1D       4        -1.4000   15.9994     
    35      AO1      1    HAP      O2C       3        -1.4000   15.9994     
    36      AO1      1    HAP      O2D       4        -1.4000   15.9994      
    37       AP      1    HAP      P1C       3         2.6000   30.9738
    38       AP      1    HAP      P1D       4         2.6000   30.9738
    39      ACa      1    HAP      CaC      19         2.0000   40.0800
    40      ACa      1    HAP      CaD      20         2.0000   40.0800
    41      AO1      1    HAP      O1E       5        -1.4000   15.9994
    42      AO1      1    HAP      O1F       6        -1.4000   15.9994
    43      AO1      1    HAP      O2E       5        -1.4000   15.9994   
    44      AO1      1    HAP      O2F       6        -1.4000   15.9994
    45       AP      1    HAP      P1E       5         2.6000   30.9738   
    46       AP      1    HAP      P1F       6         2.6000   30.9738
    47      ACa      1    HAP      CaE      21         2.0000   40.0800
    48      ACa      1    HAP      CaF      22         2.0000   40.0800
    49      AO1      1    HAP      O1G       7        -1.4000   15.9994     
    50      AO1      1    HAP      O1H       8        -1.4000   15.9994
    51      AO1      1    HAP      O2G       7        -1.4000   15.9994   
    52      AO1      1    HAP      O2H       8        -1.4000   15.9994
    53       AP      1    HAP      P1G       7         2.6000   30.9738   
    54       AP      1    HAP      P1H       8         2.6000   30.9738
    55      ACa      1    HAP      CaG      23         2.0000   40.0800
    56      ACa      1    HAP      CaH      24         2.0000   40.0800
    57      AO1      1    HAP      O1I       9        -1.4000   15.9994     
    58      AO1      1    HAP      O1J      10        -1.4000   15.9994
    59      AO1      1    HAP      O2I       9        -1.4000   15.9994
    60      AO1      1    HAP      O2J      10        -1.4000   15.9994 
    61       AP      1    HAP      P1I       9         2.6000   30.9738   
    62       AP      1    HAP      P1J      10         2.6000   30.9738   
    63      ACa      1    HAP      CaI      25         2.0000   40.0800
    64      ACa      1    HAP      CaJ      26         2.0000   40.0800
    65      AO1      1    HAP      O1K      11        -1.4000   15.9994     
    66      AO1      1    HAP      O1L      12        -1.4000   15.9994
    67      AO1      1    HAP      O2K      11        -1.4000   15.9994
    68      AO1      1    HAP      O2L      12        -1.4000   15.9994
    69       AP      1    HAP      P1K      11         2.6000   30.9738   
    70       AP      1    HAP      P1L      12         2.6000   30.9738   
    71      ACa      1    HAP      CaK      27         2.0000   40.0800
    72      ACa      1    HAP      CaL      28         2.0000   40.0800     
    73      ACa      1    HAP      CaM      29         2.0000   40.0800
    74      ACa      1    HAP      CaN      30         2.0000   40.0800   
    75      ACa      1    HAP      CaO      31         2.0000   40.0800
    76      ACa      1    HAP      CaP      32         2.0000   40.0800
    77      ACa      1    HAP      CaQ      33         2.0000   40.0800
    78      ACa      1    HAP      CaR      34         2.0000   40.0800
    79      ACa      1    HAP      CaS      35         2.0000   40.0800     
    80      ACa      1    HAP      CaT      36         2.0000   40.0800
    81      AO4      1    HAP      O4A      13        -1.6000   15.9994
    82      AO4      1    HAP      O4B      14        -1.6000   15.9994
    83       AH      1    HAP      H1A      13         0.6000   1.00800
    84       AH      1    HAP      H1B      14         0.6000   1.00800     
    85      AO4      1    HAP      O4C      15        -1.6000   15.9994
    86      AO4      1    HAP      O4D      16        -1.6000   15.9994
    87       AH      1    HAP      H1C      15         0.6000   1.00800
    88       AH      1    HAP      H1D      16         0.6000   1.00800     
 

[ bonds ]
;aqui se ponen los enlaces que se encuentran el pdb
;  ai    aj funct           r0          kr
      29       1       1 0.154E+00 6.0706E+03
      29      19       1 0.154E+00 6.0706E+03
      29      25       1 0.154E+00 6.0706E+03
      29      27       1 0.154E+00 6.0706E+03
      30       2       1 0.154E+00 6.0706E+03
      30      20       1 0.154E+00 6.0706E+03
      30      26       1 0.154E+00 6.0706E+03
      30      28       1 0.154E+00 6.0706E+03
      37       3       1 0.154E+00 6.0706E+03
      37      21       1 0.154E+00 6.0706E+03
      37      33       1 0.154E+00 6.0706E+03
      37      35       1 0.154E+00 6.0706E+03
      38       4       1 0.154E+00 6.0706E+03
      38      22       1 0.154E+00 6.0706E+03
      38      34       1 0.154E+00 6.0706E+03
      38      36       1 0.154E+00 6.0706E+03
      45       5       1 0.154E+00 6.0706E+03
      45      23       1 0.154E+00 6.0706E+03
      45      41       1 0.154E+00 6.0706E+03
      45      43       1 0.154E+00 6.0706E+03
      46       6       1 0.154E+00 6.0706E+03
      46      24       1 0.154E+00 6.0706E+03
      46      42       1 0.154E+00 6.0706E+03
      46      44       1 0.154E+00 6.0706E+03
      53       7       1 0.154E+00 6.0706E+03
      53      13       1 0.154E+00 6.0706E+03
      53      49       1 0.154E+00 6.0706E+03
      53      51       1 0.154E+00 6.0706E+03
      54       8       1 0.154E+00 6.0706E+03
      54      14       1 0.154E+00 6.0706E+03
      54      50       1 0.154E+00 6.0706E+03
      54      52       1 0.154E+00 6.0706E+03
      61       9       1 0.154E+00 6.0706E+03
      61      15       1 0.154E+00 6.0706E+03
      61      57       1 0.154E+00 6.0706E+03
      61      59       1 0.154E+00 6.0706E+03     
      62      10       1 0.154E+00 6.0706E+03
      62      16       1 0.154E+00 6.0706E+03
      62      58       1 0.154E+00 6.0706E+03
      62      60       1 0.154E+00 6.0706E+03   
      69      11       1 0.154E+00 6.0706E+03
      69      17       1 0.154E+00 6.0706E+03
      69      65       1 0.154E+00 6.0706E+03
      69      67       1 0.154E+00 6.0706E+03   
      70      12       1 0.154E+00 6.0706E+03
      70      18       1 0.154E+00 6.0706E+03
      70      66       1 0.154E+00 6.0706E+03
      70      68       1 0.154E+00 6.0706E+03   
      81      83       1 0.09600E+00 1.25317e+04
      82      84       1 0.09600E+00 1.25317e+04     
      85      87       1 0.09600E+00 1.25317e+04
      86      88       1 0.09600E+00 1.25317e+04
    
             
[ pairs ]
;  ai    aj funct
   
[ angles ]
;aqui se ponen los angulos posibles entre los enlaces
;  ai    aj    ak funct             0         k0
       1      29      19       1 1.911E+00  4.973342e+04
       1      29      25       1 1.911E+00  4.973342e+04
       1      29      27       1 1.911E+00  4.973342e+04
      19      29      25       1 1.911E+00  4.973342e+04
      19      29      27       1 1.911E+00  4.973342e+04
      25      29      27       1 1.911E+00  4.973342e+04
       2      30      20       1 1.911E+00  4.973342e+04
       2      30      26       1 1.911E+00  4.973342e+04
       2      30      28       1 1.911E+00  4.973342e+04
      20      30      26       1 1.911E+00  4.973342e+04
      20      30      28       1 1.911E+00  4.973342e+04
      26      30      28       1 1.911E+00  4.973342e+04
       3      37      21       1 1.911E+00  4.973342e+04
       3      37      33       1 1.911E+00  4.973342e+04
       3      37      35       1 1.911E+00  4.973342e+04
      21      37      33       1 1.911E+00  4.973342e+04
      21      37      35       1 1.911E+00  4.973342e+04
      33      37      35       1 1.911E+00  4.973342e+04
       4      38      22       1 1.911E+00  4.973342e+04
       4      38      34       1 1.911E+00  4.973342e+04
       4      38      36       1 1.911E+00  4.973342e+04
      22      38      34       1 1.911E+00  4.973342e+04
      22      38      36       1 1.911E+00  4.973342e+04
      34      38      36       1 1.911E+00  4.973342e+04
       5      45      23       1 1.911E+00  4.973342e+04
       5      45      41       1 1.911E+00  4.973342e+04
       5      45      43       1 1.911E+00  4.973342e+04
      23      45      41       1 1.911E+00  4.973342e+04
      23      45      43       1 1.911E+00  4.973342e+04
      41      45      43       1 1.911E+00  4.973342e+04
       6      46      24       1 1.911E+00  4.973342e+04
       6      46      42       1 1.911E+00  4.973342e+04
       6      46      44       1 1.911E+00  4.973342e+04
      24      46      42       1 1.911E+00  4.973342e+04
      24      46      44       1 1.911E+00  4.973342e+04
      42      46      44       1 1.911E+00  4.973342e+04
       7      53      13       1 1.911E+00  4.973342e+04
       7      53      49       1 1.911E+00  4.973342e+04
       7      53      51       1 1.911E+00  4.973342e+04
      13      53      49       1 1.911E+00  4.973342e+04
      13      53      51       1 1.911E+00  4.973342e+04
      49      53      51       1 1.911E+00  4.973342e+04
       8      54      14       1 1.911E+00  4.973342e+04
       8      54      50       1 1.911E+00  4.973342e+04
       8      54      52       1 1.911E+00  4.973342e+04
      14      54      50       1 1.911E+00  4.973342e+04
      14      54      52       1 1.911E+00  4.973342e+04
      50      54      52       1 1.911E+00  4.973342e+04
       9      61      15       1 1.911E+00  4.973342e+04
       9      61      57       1 1.911E+00  4.973342e+04
       9      61      59       1 1.911E+00  4.973342e+04
      15      61      57       1 1.911E+00  4.973342e+04
      15      61      59       1 1.911E+00  4.973342e+04
      57      61      59       1 1.911E+00  4.973342e+04
      10      62      16       1 1.911E+00  4.973342e+04
      10      62      58       1 1.911E+00  4.973342e+04
      10      62      60       1 1.911E+00  4.973342e+04
      16      62      58       1 1.911E+00  4.973342e+04
      16      62      60       1 1.911E+00  4.973342e+04
      58      62      60       1 1.911E+00  4.973342e+04
      11      69      17       1 1.911E+00  4.973342e+04
      11      69      65       1 1.911E+00  4.973342e+04
      11      69      67       1 1.911E+00  4.973342e+04
      17      69      65       1 1.911E+00  4.973342e+04
      17      69      67       1 1.911E+00  4.973342e+04
      65      69      67       1 1.911E+00  4.973342e+04
      12      70      18       1 1.911E+00  4.973342e+04
      12      70      66       1 1.911E+00  4.973342e+04
      12      70      68       1 1.911E+00  4.973342e+04
      18      70      66       1 1.911E+00  4.973342e+04
      18      70      68       1 1.911E+00  4.973342e+04
      66      70      68       1 1.911E+00  4.973342e+04
 
[ dihedrals ]
;  ai    aj    ak    al funct   phi0     cp     mult

; Include Position restraint file
;#ifdef POSRES_HAP
;#include "hap_posre.itp"
;#endif


3- hap_posre.itp
; position restraints for HAP of Generated by trjconv :
Model-4-HAP-scelda2-100-10bx5c t=   0.00000

[ position_restraints ]
;  i funct       fcx        fcy        fcz
   1    1     1000000   1000000   1000000
   2    1     1000000   1000000   1000000
   3    1     1000000   1000000   1000000
   4    1     1000000   1000000   1000000
   5    1     1000000   1000000   1000000
   6    1     1000000   1000000   1000000
   7    1     1000000   1000000   1000000
   8    1     1000000   1000000   1000000
   9    1     1000000   1000000   1000000
  10    1     1000000   1000000   1000000
  11    1     1000000   1000000   1000000
  12    1     1000000   1000000   1000000
  13    1     1000000   1000000   1000000
  14    1     1000000   1000000   1000000
  15    1     1000000   1000000   1000000
  16    1     1000000   1000000   1000000
  17    1     1000000   1000000   1000000
  18    1     1000000   1000000   1000000
  19    1     1000000   1000000   1000000
  20    1     1000000   1000000   1000000
  21    1     1000000   1000000   1000000
  22    1     1000000   1000000   1000000
  23    1     1000000   1000000   1000000
  24    1     1000000   1000000   1000000
  25    1     1000000   1000000   1000000
  26    1     1000000   1000000   1000000
  27    1     1000000   1000000   1000000
  28    1     1000000   1000000   1000000
  29    1     1000000   1000000   1000000
  30    1     1000000   1000000   1000000
  31    1     1000000   1000000   1000000
  32    1     1000000   1000000   1000000
  33    1     1000000   1000000   1000000
  34    1     1000000   1000000   1000000
  35    1     1000000   1000000   1000000
  36    1     1000000   1000000   1000000
  37    1     1000000   1000000   1000000
  38    1     1000000   1000000   1000000
  39    1     1000000   1000000   1000000
  40    1     1000000   1000000   1000000
  41    1     1000000   1000000   1000000
  42    1     1000000   1000000   1000000
  43    1     1000000   1000000   1000000
  44    1     1000000   1000000   1000000
  45    1     1000000   1000000   1000000
  46    1     1000000   1000000   1000000
  47    1     1000000   1000000   1000000
  48    1     1000000   1000000   1000000
  49    1     1000000   1000000   1000000
  50    1     1000000   1000000   1000000
  51    1     1000000   1000000   1000000
  52    1     1000000   1000000   1000000
  53    1     1000000   1000000   1000000
  54    1     1000000   1000000   1000000
  55    1     1000000   1000000   1000000
  56    1     1000000   1000000   1000000
  57    1     1000000   1000000   1000000
  58    1     1000000   1000000   1000000
  59    1     1000000   1000000   1000000
  60    1     1000000   1000000   1000000
  61    1     1000000   1000000   1000000
  62    1     1000000   1000000   1000000
  63    1     1000000   1000000   1000000
  64    1     1000000   1000000   1000000
  65    1     1000000   1000000   1000000
  66    1     1000000   1000000   1000000
  67    1     1000000   1000000   1000000
  68    1     1000000   1000000   1000000
  69    1     1000000   1000000   1000000
  70    1     1000000   1000000   1000000
  71    1     1000000   1000000   1000000
  72    1     1000000   1000000   1000000
  73    1     1000000   1000000   1000000
  74    1     1000000   1000000   1000000
  75    1     1000000   1000000   1000000
  76    1     1000000   1000000   1000000
  77    1     1000000   1000000   1000000
  78    1     1000000   1000000   1000000
  79    1     1000000   1000000   1000000
  80    1     1000000   1000000   1000000
  81    1     1000000   1000000   1000000
  82    1     1000000   1000000   1000000
  83    1     1000000   1000000   1000000
  84    1     1000000   1000000   1000000
  85    1     1000000   1000000   1000000
  86    1     1000000   1000000   1000000
  87    1     1000000   1000000   1000000
  88    1     1000000   1000000   1000000

4- topol.top
; Include forcefield parameters
#include "gromos_HAP.ff/forcefield.itp"


; Include HAP crystal slap topology
#include "HAP-MODEL4-100.itp"
#ifdef POSRES_HAP
#include "hap_posre.itp"
#endif


; Include water topology
#include "gromos53a6_HAP.ff/spc.itp"

#ifdef POSRES_WATER
; Position restraint for each water oxygen
[ position_restraints ]
;  i funct       fcx        fcy        fcz
   1    1       1000       1000       1000
#endif

; Include topology for ions
#include "gromos53a6_HAP.ff/ions.itp"

[ system ]
; Name
newbox-pep2 in water

[ molecules ]
; Compound        #mols
HAP                1

Looking forward to your comments...

Cheers,
Ramon


On Wed, 25 Jul 2012 15:10:43 -0400, Justin Lemkul wrote
> On 7/25/12 2:32 PM, Ramon Garduno wrote:
> > Dear gmx friends:
> >
> > We are modeling a solvated hydroxyapatite(HAP)-protein complex. We have
> > minimized and equilibrated this system to 300K under NVT.
> >
> > The odd behavior is observed when we start an NPT simulation. In the very
> > first ps we observed that the oxygens bound (initially) to phosphorous in
> > phosphate tetrahedon assume a geometry in which all four oxygens are grouped
> > together like this P=O, however we never receive an error message.
> >
> > The bond lenghts have been constrained using the SHAKE algorithm.
> >
> > HAP is in the form of a crystal slab. The HAP parameters we have used were
> > taken from Dinesh-Katti's paper [Polymer 48 (2007) 664-674], in turn, Katti
> > took the HAP parameters from Hauptmann [Phys Chem Chem Phys  (2003) 5,
635-639].
> >
> > Katti's parameters were parameterized to CVFF. We have made ​​the
> > corresponding unit convertions to fit those requiered in GROMACS v4.5. In
> > short, we have used NON_BONDED (Homonuclear and Heteronuclear van der Waals
> > terms), BONDED parameters (ffnonbonded.itp and HAP.itp), and the same PARTIAL
> > ATOMIC CHARGES as those reported by Katti's group.
> >
> > In order to avoid the odd behaviour observed in the tetrahedral phosphate, we
> > have used strong position restraints but the odd behaviour is still present.
> > We also used freeze groups but with this command it is not possible to
> > equilibrate the system under NPT.
> >
> > Do you have some suggestions to solve this problem?
> >
> 
> It sounds like a topology error, but without seeing the .itp file, 
> it's hard to guess.
> 
> -Justin
> 
> -- 
> ========================================
> 
> Justin A. Lemkul, Ph.D.
> Research Scientist
> Department of Biochemistry
> Virginia Tech
> Blacksburg, VA
> jalemkul[at]vt.edu | (540) 231-9080
> http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin
> 
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