Colvin,
> What i mean is that, i have done resp calculations on 24 conformations and
> can i average the resp charges?
>
> As i read this from http://q4md-forcefieldtools.org/RED/FAQ-I.php
These FAQ are old/outdated(2004!) (they should rewritten). Since that
time R.E.D. has changed a lot, and we ALSO did learn a lot.
You are right "charge averaging" is not correct in these FAQ-I:
My mistake. Sorry for that... Thanks for pointing this out.
> "Do you average RESP results on many orientations?"
No, we do use charge fitting based on multiple-orientations and/or
multiple-conformations and/or multiple molecules.
> "Yes, we do average RESP results on 'different' orientations: we called it
> multi-orientation-RESP fit by analogy to the multi-conformational RESP fit,
> see below"
this is ambiguous you are right! multi-orientation-RESP fit is about
"charge fitting" and not "charge averaging". There is not arithmetic
mean in RESP charge fitting/derivation.
> Or do i misunderstand your meaning?
>
> how many conformations should be use to be useful? is that depends on the
> molecule itself?
You can look at
Cieplak et al Application of the multimolecule and multiconformational
RESP methodology to biopolymers: Charge derivation for DNA, RNA, and
proteins. J. Comput. Chem. 1995, 16, 1357-1377
& and also:
http://www.rsc.org/Publishing/Journals/CP/article.asp?doi=c0cp00111b
regards, Francois
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Received on Wed Jun 30 2010 - 02:30:09 PDT
