On 07/03/13 12:27, Dave wrote:
> Hi -
>
> I'm working on a mammalian derived crystal. In a few chains where I can see the N-terminus, it appears that they are acetylated. I looked for previous discussion on how to deal with this, and I was wondering how exactly to deal with this in coot as of 2013.
>
> Thus far, I added an ala to the n-terminus, then used
> extensions>modelling>replace residue
> to mutate to ACE
That sounds fine.
>
> I'm running coot 0.7 stable release sept 2012.
>
> I'm not seeing a bond between the original N-term N atom and the C of he acetyl group
Coot won't link het groups that are non-polymers. Maybe there should be
an exception for ACE.
>
> Real Space Refine Zone and Regularize Zone do not like the setup.
quite right.
> I'm sure I need to define some things, but haven't dealt with this before, as for things like this, I used to switch to xfit.
:-(
I suspect that you need to not tell coot that ACE is a non-polymer - you
can do that by either copying and hand-editing the cif file or using
Edit -> Restraints -> ACE -> then change "non-polymer" to "L-peptide",
Apply.
Then I would do a sphere refine.
>
> Would it be better to ask at CCP4?
>
:-(
Paul.
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