[gmx-users] Non-bonded interaction

라지브간디 rajiv at kaist.ac.kr
Sat May 31 14:43:42 CEST 2014

Dear justin,

Could tell me how do I convert those non-bonded values between CHARMM and gromos431 ?

I am unaware of this conversion.

Thanks in advance.

On 5/30/14, 11:51 AM, ????? wrote: 
> Dear justin, 
> Thank your for your clear answer. 
> The parameters are specifically written for CHARMM force field based on the experimental results. 
> Particularly, charges and non-bonded interaction values for ligand molecule of CO ( Carbon Monoxide) in Myoglobin are written in literature. 
> Since Gromos 43a1 has parameter for heme with CO, therefore I asked you " Is that possible to use only this CO ligand charges and non-bonded values derive 
> d from experimental and written in CHARMM ff ?. 
> In other case, shall I use this CHARMM ff values for CO in CHARMM27/36 provided by groamcs without doing any conversion ? 

Yes, you need to convert the units (CHARMM and Gromacs use different 
conventions), but otherwise those parameters can be used directly with CHARMM27 
or CHARMM36. 


> Thanks in advance. 
> On 5/29/14, 10:13 PM, ????? wrote: 
>> Dear Justin, 
>> Thanks for your 
>> reply. 
>> I am not mixing up the parameter here. 
>> What i am trying to do here 
>> In order to reproduce the dipole moments of the CO, I have to 
>> follow up the specific charges and non-bonded interaction values specified in 
>> literature in CHARMM format ( For C atom, charge -0.75, ?=0.0262 
>> & ? = 3.83) ( For O atom, charge -0.85, ?=0.0262 & ? = 
>> 3.83). 
> "CHARMM format" and "CHARMM force field" are different, so what is the origin of 
> those parameters? Were they developed specifically for CHARMM or some other 
> force field? If these parameters were not specifically designed to be 
> consistent within Gromos96 43A1, my original point stands - they cannot be 
> combined with a force field for which they were not self-consistently derived. 
>> Could you tell how it can be done? If i cant use them in 
>> gromos43a1 ff, possible to use in charmm27 provided by gromacs package? or it 
>> does need any conversion to use in gromacs-charmm27 ff? 
> Both CHARMM27 and CHARMM36 are fully supported by Gromacs. 
> -Justin

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