From: Fotis Baltoumas (fbaltoumas_at_biol.uoa.gr)
Date: Mon Nov 21 2016 - 09:54:33 CST
Hello,
When you run Martini simulations with NAMD, you should enable 
"MartiniSwitching    on" in your configuration file.
This, essentially, does what you ask: it enables the use of different 
switchdist options for Lennard-Jones and Coulomb electrostatics. The 
switchdist that can be set in the configuration file is actually to 
describe the option for LJ interactions, while the coulombic switchdist 
is automatically set to 0 (this is hardcoded in the NAMD source and 
enabled with MartiniSwitching).
In other words, in your MARTINI configuration file you should include 
the following:
# Force-Field Parameters
exclude             1-2
1-4scaling          1.0
cutoff              12.0
martiniSwitching    on
PME                 off
switching           on
switchdist           9.0
pairlistdist        14
dielectric         15.0
All of this is explained in more detail in the Residue-Based 
Coarse-Graining tutorial files (although, technically, they SHOULD be 
part of the User's Guide, so that people know how the force field is 
ACTUALLY implemented in NAMD):
http://www.ks.uiuc.edu/Training/Tutorials/martini/
Good luck,
Fotis
On 11/21/2016 02:17 PM, Peter Mawanga wrote:
> Hello everyone
>
> Is it feasible to use different /switchdist/ for LJ and electrostatic 
> interactions in *Martini* simulations? I would like to switch LJ from 
> say 9 Å and electrostatics from 0 Å to final /cutoff/ distance.
>
> htp://www.ks.uiuc.edu/Research/namd/2.9/ug/node23.html#SECTION00082300000000000000 
> <http://www.ks.uiuc.edu/Research/namd/2.9/ug/node23.html#SECTION00082300000000000000>
>
> As per the NAMD literature available, this should be possible, but 
> cannot figure out how to implement the same:
>
> http://www.sciencedirect.com/science/article/pii/S1047847706002541
> http://journals.plos.org/ploscompbiol/article?id=10.1371%2Fjournal.pcbi.1003488
> http://pubs.acs.org/doi/abs/10.1021/ci500007n
> http://pubs.acs.org/doi/abs/10.1021/jp0550816
> http://pubs.acs.org/doi/abs/10.1021/ct300696c
> http://www.sciencedirect.com/science/article/pii/S0969212609000720
>
> Please suggest some way of doing so if it can be done.
>
> Cheers
> Peter
-- ******************************************* Fotis A. Baltoumas Phd Candidate, Bioinformatics Postgraduate Programme Department of Cell Biology and Biophysics Faculty of Biology, University of Athens Panepistimiopolis, Athens 157 01, GREECE -------------------------------------- email : fbaltoumas_at_biol.uoa.gr http://biophysics.biol.uoa.gr http://bioinformatics.biol.uoa.gr *******************************************
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