[gmx-users] Fwd: is there martini CG parameters for K+ ion?

[Peter Kroon]

Hi,


disturbing to hear you can't register on our forums. We've been having
some trouble with the website, so we'll definitely look into it.

As for the science: Na+ and K+ are identical in Martini. The size
difference is compensated by the implicit solvation shell anyway. You'd
have to look into the literature to find a validation for this though, I
don't have it handy.


Good luck,

Peter


On 17-08-16 20:26, li he wrote:
> Dear gmxers,
> I am not sure if I'd better post my question here, but the martini forum
> http://www.cgmartini.nl/index.php/forum  does not allow me register and
> post my
> question there.
> I am trying to simulate some KCl solution, but only find martini CG Na+
> parameters
> at http://cgmartini.nl/images/parameters/ITP/martini_v2.0_ions.itp
> I am wondering where I can find martini parameters for K+ ion, or can I
> just use martini
> Na+ parameters for K+?
> If there is a martini parameter of K+, I could image it should be Qd bead
> with +1 charge, exactly the same as Na+ parameters at the above link. Yes,
> it is upsetting to use the same parameter for Na+ and K+, but we have to
> admit the current martini force field is not very fine tuned, thus have to
> just use Na+ martini parameters at the above link for K+ if we want to
> simulate CG KCl or martini KCl anyway? Can this way be justified if the
> simulation results agree with the results of other studies, either
> experiments or simulations?
> Thanks a lot for your kind help, and any suggestion or comment is very
> welcome.
> Yours
> he li