From: James Starlight (jmsstarlight_at_gmail.com)
Date: Wed Nov 13 2013 - 12:11:57 CST
I'd like to specify some points about steered MD in NAMD.
1) In colvar.in I should define upperboundaries and lowerboundaries to
prevent movement of my ligand in xy plane if it leaves ligand cavity. As I
understand upperboundaries - lowerboundaries = length of the pore inside my
protein . How I could measure it ?
2) What should I do if the bulk ligand (hydrophobic contacts are the main
stabilized interactions witthin protein interior) haven't pulled from the
protein interior although of big forces been applied to all non-hydrogen
ligand atoms?
James
2013/11/12 James Starlight <jmsstarlight_at_gmail.com>
> Dear Namd users!
>
> I have some questions after studing NAMDs steered MD tutorial following
> each of its steps..
> 1) Some methodological issues. It's not clear for me how I could 1)
> obtained list of Ca atoms of my protein (I understood that I should do
> selection in VMD but how save it as the output in txt?) needed for the
> colvar.in file. Also I dont understand how I could obtain precise values
> for the lowerboundary and upperboundary XY values in colvar.in based on
> my PDB loaded in the VMD ?). Fnally does it possible to use some script in
> VMD which would automatically shows me sidechains affected ligand motion
> seen in the initial (pull) trajectory (in case of the tutorial it was some
> hydrophobic clusters)?
>
> Finally I have also theoretical question about linkage of the PMF with the
> free energy value. From the general assumption the barrier regions seen in
> the histograms (where big forces are detected) should correspond to the big
> values of delta G shouldn't it ? It there any general relationships between
> both of that parameter in MD. Does it possible to calculate precise delta G
> value of the studied process (e.g ligand dissociation) based on my SMD
> (assuming that I've simulated the investigated process several times ( in
> several windows) obtaining convergence in each of them)?
>
> Thanks for help,
>
> James
>
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