[gmx-users] g_chi and torsional angles

Sandor Lovas SandorLovas at creighton.edu
Thu Dec 1 18:27:51 CET 2005


Than I should say the angle definitions are wrong in g_chi, they do not
follow conventions, therefore, results could be misleading:

I copied here part of a structure file and the corresponding output
(chi.log)

Structure:

    1ALA      N    1   3.562   2.218   2.878  0.5075 -0.4009 -0.2929
    1ALA     H1    2   3.641   2.235   2.937  0.5503 -0.1968 -0.4035
    1ALA     H2    3   3.548   2.121   2.860 -0.4536 -0.7485  2.0694
    1ALA     H3    4   3.585   2.261   2.790  1.8632 -1.0614 -0.2916
    1ALA     CA    5   3.436   2.258   2.942  0.5631 -0.0157 -0.4098
    1ALA     CB    6   3.455   2.406   2.977 -0.2534 -0.0442  0.1426
    1ALA      C    7   3.306   2.236   2.865  0.1307 -0.4194  0.4205
    1ALA      O    8   3.292   2.152   2.776 -0.2003  0.1358 -0.0557
    2ALA      N    9   3.200   2.296   2.918  0.2834  0.1087  0.1264
    2ALA      H   10   3.202   2.333   3.010  0.9805 -1.2027  0.6552
    2ALA     CA   11   3.076   2.321   2.842  0.1590  0.8241  0.5482
    2ALA     CB   12   2.969   2.364   2.943 -0.4890 -0.0032  0.2365
    2ALA      C   13   3.103   2.431   2.740  0.4232  0.2444 -0.0133
    2ALA      O   14   3.189   2.518   2.756  0.2789  0.4016 -0.0868
    3GLY      N   15   3.020   2.449   2.637 -0.1869  0.1175  0.4532
    3GLY      H   16   2.955   2.380   2.605 -0.1420  0.4072 -0.2725
    3GLY     CA   17   3.035   2.565   2.548 -0.5698 -0.0023  0.2228
    3GLY      C   18   3.044   2.528   2.400 -0.4774  0.2780  0.1559
    3GLY      O   19   3.132   2.456   2.353 -0.5339  0.1656  0.2364
    4ASP      N   20   2.959   2.597   2.323 -0.4545  0.1756  0.0327
    4ASP      H   21   2.887   2.659   2.353 -0.9106  0.3980 -1.4441
    4ASP     CA   22   2.949   2.590   2.177 -0.1954  0.5615 -0.0061
    4ASP     CB   23   2.799   2.585   2.146 -0.1315  0.2244 -0.2770
    4ASP     CG   24   2.724   2.712   2.189  0.3699  0.4550 -0.0780
    4ASP    OD1   25   2.674   2.779   2.097  0.1515 -0.1099 -0.3718
    4ASP    OD2   26   2.737   2.754   2.306  0.6242  0.3487 -0.0585
    4ASP      C   27   3.022   2.709   2.112  0.0970  0.0899 -0.5616
    4ASP      O   28   3.143   2.714   2.132  0.0381 -0.0732 -0.1616
    5TYR      N   29   2.950   2.794   2.040 -0.4454 -0.2776 -0.4590
    5TYR      H   30   2.851   2.802   2.052 -0.5294 -0.6510 -0.8740
    5TYR     CA   31   3.004   2.879   1.933 -0.2098  0.1104 -0.0357
    5TYR     CB   32   2.894   2.891   1.827 -0.2574 -0.0793 -0.0072
    5TYR     CG   33   2.876   2.774   1.730  0.3700 -0.3455  0.1969
    5TYR    CD1   34   2.816   2.654   1.767  0.5287 -0.3086  0.5728
    5TYR    HD1   35   2.753   2.645   1.854 -1.7704  0.0222 -0.9670
    5TYR    CD2   36   2.938   2.789   1.606  0.3357 -0.2619  0.1894
    5TYR    HD2   37   2.986   2.881   1.577  0.1702 -0.5658 -1.1095
    5TYR    CE1   38   2.819   2.549   1.676 -0.1451 -0.1527  0.3476
    5TYR    HE1   39   2.758   2.466   1.708  1.3566 -0.1348  3.8080
    5TYR    CE2   40   2.944   2.680   1.520  0.2326 -0.3585  0.3032
    5TYR    HE2   41   2.977   2.689   1.417 -1.0434 -2.2192 -0.3202
    5TYR     CZ   42   2.882   2.560   1.553 -0.7032  0.0552  0.0820
    5TYR     OH   43   2.866   2.467   1.456  0.4939  0.4361 -0.4984
    5TYR     HH   44   2.780   2.420   1.474 -2.1323  4.9834  0.3245
    5TYR      C   45   3.042   3.012   1.998 -0.0187 -0.1974  0.4917
    5TYR      O   46   2.951   3.081   2.044 -0.2640  0.1173 -0.4352
    6TYR      N   47   3.169   3.015   2.038  0.3531  0.1647 -0.6888
    6TYR      H   48   3.232   2.938   2.027 -1.0865 -1.2089  0.2993
    6TYR     CA   49   3.240   3.129   2.097 -0.4699  0.2177  0.2191
    6TYR     CB   50   3.265   3.096   2.245  0.0316 -0.1360  0.0573
    6TYR     CG   51   3.128   3.101   2.312 -0.1894  0.2743 -0.4176
    6TYR    CD1   52   3.057   2.985   2.342  0.0967  0.3673  0.6427
    6TYR    HD1   53   3.096   2.888   2.314 -1.3609 -0.2707  0.7406
    6TYR    CD2   54   3.087   3.229   2.348 -0.7178  0.0609 -0.2409
    6TYR    HD2   55   3.141   3.316   2.314  0.1695 -0.5419 -0.4301
    6TYR    CE1   56   2.938   2.999   2.412  0.1973 -0.5481  1.0083
    6TYR    HE1   57   2.870   2.916   2.425  0.2410 -0.4729  1.7892
    6TYR    CE2   58   2.974   3.240   2.427 -0.4928  0.3655  0.0422
    6TYR    HE2   59   2.941   3.338   2.459 -0.5823  1.1613 -2.3012
    6TYR     CZ   60   2.901   3.125   2.458 -0.2228 -0.0175 -0.7255
    6TYR     OH   61   2.792   3.135   2.539  0.2389  0.0429 -0.1030
    6TYR     HH   62   2.756   3.228   2.547  1.1846  0.4551 -0.4195
    6TYR      C   63   3.376   3.142   2.029 -0.6233 -0.0397 -0.1371
    6TYR      O   64   3.425   3.049   1.965  0.3830  0.1292  0.3743
    7NH2      N   65   3.427   3.264   2.020  0.4141 -0.4216  0.4585
    7NH2     H1   66   3.379   3.345   2.055  1.0105 -0.0315  0.4032
    7NH2     H2   67   3.504   3.269   1.956 -2.2804  2.6664 -2.9527


Part of chi.log:

Residue ALA1
 Angle [   AI,   AJ,   AK,   AL]  #tr/ns  S^2D  
--------------------------------------------
   Phi [    2,    1,    5,    7]   27.55    0.00
   Psi [    1,    5,    7,    8]    6.90    0.87

Residue ALA2
 Angle [   AI,   AJ,   AK,   AL]  #tr/ns  S^2D  
--------------------------------------------
   Phi [   10,    9,   11,   13]   10.20    0.73
   Psi [    9,   11,   13,   14]    9.40    0.79

Residue GLY3
 Angle [   AI,   AJ,   AK,   AL]  #tr/ns  S^2D  
--------------------------------------------
   Phi [   16,   15,   17,   18]    9.00    0.52
   Psi [   15,   17,   18,   19]   10.40    0.15

Residue ASP4
 Angle [   AI,   AJ,   AK,   AL]  #tr/ns  S^2D  
--------------------------------------------
   Phi [   21,   20,   22,   27]    0.90    0.89
   Psi [   20,   22,   27,   28]    0.30    0.88
   Chi1[   20,   22,   23,   24]    0.25    0.88
   Chi2[   22,   23,   24,   25]    7.90    0.00

Residue TYR5
 Angle [   AI,   AJ,   AK,   AL]  #tr/ns  S^2D  
--------------------------------------------
   Phi [   30,   29,   31,   45]    2.15    0.85
   Psi [   29,   31,   45,   46]    4.75    0.74
   Chi1[   29,   31,   32,   33]    0.70    0.53
   Chi2[   31,   32,   33,   34]    0.25    0.31

Residue TYR6
 Angle [   AI,   AJ,   AK,   AL]  #tr/ns  S^2D  
--------------------------------------------
   Phi [   48,   47,   49,   63]   10.25    0.84
   Psi [   47,   49,   63,   64]    7.75    0.21
   Chi1[   47,   49,   50,   51]    1.30    0.44
   Chi2[   49,   50,   51,   52]    0.50    0.00


For example: for ALA2 the phi should be 7, 9, 11, 13  : C(i-1), N(i),
CA(i), C(i)
you could check for the other residues and all phi, psi are wrongly
defined.

Sandor


-- 
___________________________________________________________________________
Dr. Sandor Lovas, Associate Professor  |   Phone: 402-280-5753
Department of Biomedical Sciences      |   Fax:   402-280-2690
Creighton University                   |   http://bif1.creighton.edu
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