Re: AMBER: RESP charges in Fe+3 heme system

From: FyD <>
Date: Thu, 26 Aug 2004 20:33:09 +0200


Metal, multiplicity different of 1, radii problem...

> I am calculating partial charges for a heme-Fe+3 system. The Fe atom is
> bounded to the 4 pirrolic N, a SH2 as ligand and the proximal histidine.
> The total charge or the system is +1. Using a BLYP/6-31G* basis, I have
> obtained a MK partial charge for the Fe atom= 1.36. But RESP partial
> charges at the same lavel of approximation, give me a Fe partial charge=
> -1.9. That is unreasonable for a Fe+3 atomic center. I am using the RED
> program and a Fe atomic radius of 1.8. I would like to use RESP partial
> charge in order to define atomic similarities and groups of atoms with
> a net total partial charges. Can anybody suggest me what could be wrong
> in the RESP calculation?

If you agree to share more information, I would be very interested to look at
your data...

Regards, Francois
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Received on Thu Sep 02 2004 - 01:15:11 PDT
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