-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hello Helene--
> I am running calculations on a modular protein (4 modules) of 270 amino
> acids. I am trying to refine the NMR structure calculated by someoneelse
> (with cyana followed with minimization with cns) using the same restraints
> + 2 sets of dipolar couplings (NH only) in 2 different media (phage and
> peg). I am using the refine.py script. So the tensors are allowed to vary,
> but I have an initial guess from Module on the preliminary NMR structures.
> 
> The sole changes I have made in the refine.py script concern the restraint
> files.
> The tensors were introduced with 700 and 701 numbering (as the residue
> numbers for my protein begin at 355 and finish at 626.
> 

This shouldn't matter as the psuedo atoms have a different segment name.

> The modules are supposed to have only a limited conformational freedom,
> and I have maintained the gyration potential (does -it make sense for an
> elongated modular protein which is highly anisotropic? (estimated
> anisotropy of 4)?

If shape of the overall structure doesn't significantly differ from an
ellipsoid and is expected to be well-packed then use of Vgyr should be
safe. 

> *--- Dynamics ---- step=      0 ---- time=         0 ---- delta_t=
> 0.001 --*
> | E(kin)+E(poten)=           nan E(kin)=      4341.138 temperature=
> 2889.629 |
> |   E(poten)=           nan       grad=           nan      ANGL=
> 66.7351079 |
> |       BOND=     1.7099773       CDIH=    99.7048545      HBDA=
> nan |
> |       IMPR=     1.8225389       RAMA=    -2.6377402       VDW=
> 19.7891008 |
> |       Vgyr= 12721.0179159        noe=    33.4141355       rdc=
> 129.1452028 |
> *------------------------------------------------------------------------------*

> "/PROG/LINUX/prog/Xplor-NIH/xplor-nih-2.26/python/wrappers/publicIVM.py",
> line 136, in step
>     def step(self, *args, **kwargs): return
> _publicIVM.PublicIVM_step(self, *args, **kwargs)
> SystemError: xplor-nih error: eigen: 2 off-diagonal elements on an
> intermediate tridiagonal form did not converge to zero.

It seems that the IVM crashed due to a NAN in the HBDA term. You might
place the following snippet before the first dyn.run() (line 346):

from simulationTools import analyze
print analyze(potList['HBDA'])

Hopefully this will give some insight into why the HBDA term give a NAN.

best regards--
Charles
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (GNU/Linux)
Comment: Processed by Mailcrypt 3.5.9 <http://mailcrypt.sourceforge.net/>

iEYEARECAAYFAk0CP38ACgkQPK2zrJwS/lbDEACdEpYm4NMr810qpQDQxuB+Gael
dH4An2wqQ/1A0KCwTP3A+whC6+u3UpvH
=L4vR
-----END PGP SIGNATURE-----

Reply via email to