Re: [AMBER] RESP charge calculation

From: Pengfei Li <ambermailpengfei.gmail.com>
Date: Sat, 8 Dec 2018 21:27:17 -0500

Hi Aashish,

Sorry for the late reply. I was busy in the past weeks.

I think you did something wrong in the RESP charge fitting. You might have the total charge wrong during the RESP fitting, which caused you have such dramatic RESP charges.

I have noted in the tutorial (http://ambermd.org/tutorials/advanced/tutorial20/mcpbpy.htm) that:

“Note that it is important to get the total charge right for each of these mol2 files. Because MCPB.py will add these charges together to determine the total charge for the small and large models, and applies charge restraint of the total charge for the large model during the RESP charge fitting step."

So please double check this issue.

Hope it helps,
Pengfei

> On Nov 26, 2018, at 7:43 AM, Aashish Bhatt <aashish.ph16221.inst.ac.in> wrote:
>
> Dear Sir
>
> I have heme containing protein. I have trying to get force field parameter
> of heme via MCPB.py.
> MCPB.py second step is successfully completed but in third step resp charge
> calculation.
> I am surprised that ESP charge through Gaussian is good but resp charge is
> to much high
> some carbon charges is 2.204 or -2.0254 and some hydrogen atom charges is
> -1.231 or 1.2521 some atom charges is upto 6.321.
>
> So i need your suggestion should i go with RESP charge or ESP charges.
>
> Thanking You
>
> Aashish
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Received on Sat Dec 08 2018 - 18:30:03 PST
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