Re: [AMBER] problem in solvation

From: Senthil Natesan <sen.natesan.yahoo.com>
Date: Wed, 9 Nov 2011 04:59:39 -0800 (PST)

Bill,

yes, the structure is fine.. I don't see any problem in the coordinates.
Can you please comment on the usual way of doing it ?. Initially I tried to set up the
system as Jan mentioned, preparing single pdb file but due to atom/residue numbering,
it didn't work well. Probably due to too many ligand molecules (not at the same binding pocket) ?

By looking at the structure, I could assume that the solvateOct somehow misplaced the solute as
it is dragged towards one side.

thanks for your valuable time and suggestions.

Senthil





Bill,

I am still quite new to Amber things and have used leap in the same way
as Senthil did in order to set up a protein-ligand complex. Hence, I
used something like:

p = loadpdb protein.pdb
l = loadpdb ligand.pdb
c = combine {p l}
[addions, solvateoct, saveamberparams]

The system was built and simulated properly this way. I am wondering why
this should be an unusual way. Do most people set up PDB files with the
entire complex before starting leap?

If combine works well for two objects, shouldn't it perfectly upscale
with more items? Also, why should it matter to the solvation code how
the set of coordinates it receives as input has been created?

It would be nice to see if the solvation behavior changes when Senthil
prepares his complex in one big PDB file and skips the combine step. I
don't hope so.

Jan-Philip


On 11/09/2011 12:05 AM, Bill Ross wrote:
> Hi Senthil,
>
>> complex = combine {protein HQN MYR1 MYR2 MYR3 MYR4 MYR5 MYR6}
>
> This is unusual - if you just 'savepdb complex' at this point,
> is the structure reasonable? Maybe the default coordinates of
> all these units would fall in the right place without loadpdb
> assigning them, but if so I would be surprised. But even in
> that case, you are taking a route for building the system that
> few have used before, I believe, and this could explain why it
> hasn't been seen before. Certainly it is one that I never thought
> to test.
>
> Bill
>
> _______________________________________________
> AMBER mailing list
> AMBER.ambermd.org
> http://lists.ambermd.org/mailman/listinfo/amber


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Received on Wed Nov 09 2011 - 05:30:04 PST
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