Re: Impropers in histidine residues

From: Jerome Henin (jhenin_at_cmm.chem.upenn.edu)
Date: Wed Aug 06 2008 - 16:54:15 CDT

Hi Marc,
If you don't get replies here, I would suggest the charmm.org forums
for this question. It's not unheard of to get an answer from Rick
Venable within minutes of posting there.
Cheers,
Jerome

On Sat, Aug 2, 2008 at 4:56 AM, Marc Baaden <baaden_at_smplinux.de> wrote:
>
> Hi,
>
> I am working on a system where I had to change the protonation state
> of a histidine from HSE to HSP. I was surprised to observe that this
> leads to the loss of two improper dihedrals and wonder whether this
> is expected or not.
>
> With the HSE residue there are the lines
>
> IMPR NE2 CD2 CE1 HE2 CD2 CG NE2 HD2 CE1 ND1 NE2 HE1
> IMPR NE2 CE1 CD2 HE2 CD2 NE2 CG HD2 CE1 NE2 ND1 HE1
>
> whereas for HSP there is
>
> IMPR ND1 CG CE1 HD1 ND1 CE1 CG HD1
> IMPR NE2 CD2 CE1 HE2 NE2 CE1 CD2 HE2
>
> Intuitively I would have expected that there are more impropers
> with HSP in order to ensure the planarity of the additional hydrogen.
>
> What am I missing?
>
> Thanks in advance,
> Marc Baaden
>
>
>
> --
> Dr. Marc Baaden - Institut de Biologie Physico-Chimique, Paris
> mailto:baaden_at_smplinux.de - http://www.baaden.ibpc.fr
> FAX: +33 15841 5026 - Tel: +33 15841 5176 ou +33 609 843217
>
>
>
>

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