Re: [gmx-users] charge changes in free energy calculations

2008-10-03 Thread friendli
Hi David, Thanks for clarification. Yes, you are right. I am morphing only parts of the sidechain. Qiang David Mobley wrote: Hi, As long as you end up with the same charge in the initial and final states, you should be OK. It's only if your total transformation involves a change of net

Re: [gmx-users] charge changes in free energy calculations

2008-10-02 Thread David Mobley
Hi, As long as you end up with the same charge in the initial and final states, you should be OK. It's only if your total transformation involves a change of net charge that you need to worry. So you should be fine if you turn off the charges on D, change the LJ interactions, and turn back on

Re: [gmx-users] charge changes in Free Energy calculations

2008-09-29 Thread Tsjerk Wassenaar
Hi Qiang, Couldn't you do it by shortening the chain, turning on/off one of the CH2 groups? You only have to mind perturbing the bonding and such in the right way then. Cheers, Tsjerk On Sat, Sep 27, 2008 at 6:32 PM, friendli [EMAIL PROTECTED] wrote: Dear all, I have a mutation free energy

Re: [gmx-users] charge changes in Free Energy calculations

2008-09-29 Thread friendli
Hi Tsjerk, I have been thinking about this way, but I do not think have parameters for C(-dum)-C to C-C-C, for example, the distance between the 1st and 3rd carbons. thanks Qiang Tsjerk Wassenaar wrote: Hi Qiang, Couldn't you do it by shortening the chain, turning on/off one of the CH2

[gmx-users] charge changes in Free Energy calculations

2008-09-27 Thread friendli
Dear all, I have a mutation free energy calculation from D(asp) to E(glu). The charge is not changed for the overall mutation. However, following Dr. David Mobley's suggetion, electrostatic and VDW interaction should be modified separately, so in the first step we need to turn off the charge from

[gmx-users] charge changes in free energy calculations

2008-09-26 Thread friendli
Dear all, I have a mutation free energy calculation from D(asp) to E(glu). The charge is not changed for the overall mutation. However, following Dr. David Molbey's suggesion, electrostatic and VDW interaction should be modified separately, so in the first step we need to turn off the charge