Re: [AMBER] AMBER12 - ninterface for double bilayer system

From: Ross Walker <ross.rosswalker.co.uk>
Date: Mon, 16 Jul 2012 10:58:33 -0700

Hi James,

Ben Madej might be able to comment more here since he was the one who
implemented the constant surface tension code. My understanding is that
setting the number of interfaces to 4 should be sufficient - it is basically
a scale factor for the actual surface tension value.

That said I don't think we have ever actually tried multiple bilayers so
this will definitely be an experiment. I believe the surface tension should
probably just be the same as a single bilayer but of course that will depend
if the distance between the bilayers is small such that there is substantial
interaction between the two. Either way I'd be interested to hear what you
find when you actually try it.

All the best
Ross

> -----Original Message-----
> From: James Murdock [mailto:james.murdock.86.gmx.com]
> Sent: Monday, July 16, 2012 3:31 AM
> To: amber.ambermd.org
> Subject: [AMBER] AMBER12 - ninterface for double bilayer system
>
> Dear Amber users,
>
> I'm currently interested in the simulation of a system composed by two
> bilayers separated by a water slab between those two bilayers and with
> water slabs on the simulation cell boundaries. As I intend to use
> LIPID11, a surface tension dependent FF for this system, I believe that
> the ninterface value should be adjusted accordingly to the number of
> water/lipid interfaces, following the statement on page 26 of the
> AMBER12 manual:
>
> ninterface
> Number of interfaces in the periodic box. There must be at least two
> interfaces in the periodic box. Two interfaces is appropriate for a
> lipid bilayer system and is the default value.
> So, if for a single bilayer system ninterface = 2, then for a double
> bilayer system ninterface = 4. What are your thoughts concerning this
> change?
> I am yet to discover if the surface tension value should be changed
> from the value appropriate for a single bilayer system.
>
> Regards,
> JM
> _______________________________________________
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> AMBER.ambermd.org
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Received on Mon Jul 16 2012 - 11:00:03 PDT
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