While this works, in my experience it nearly always ends up inverting
chiralities or flipping amides, or sometimes putting bonds through the
middle of rings. I mentioned this in a previous version of this thread, it
seems we are starting to repeat things.
On Oct 21, 2016 8:43 AM, "Bill Ross" <ross.cgl.ucsf.edu> wrote:
>
> >> 3. generate a reasonable starting structure for the cyclized peptide.
> > Amber is not a very good tool (generally speaking) for carrying out step
> 3.
> >
> Though not the best at it, xleap will let you construct a cyclic
> peptide. In the cmd line:
>
> > mymol = sequence { ALA ALA .. ALA } # not a chemist btw
> > edit mymol
>
> And there get used to the controls so you can select the end atoms of
> the linear molecule one by one and and crudely move each out of line, so
> that you can draw a long bond between those atoms. Then select all the
> atoms, relax selection, all the weird bonds will be fixed as the
> molecule reforms, and with luck you are done, though iterative
> selection/relaxation might be needed if kinks develop. The energy
> minimization function is based on atom hybridizations, and lacks vdw.
>
> In the end you might want to have a more powerful and used molecular
> editor program at your fingertips, but xleap is there and once upon a
> time we put some time into making it work.
>
> Bill
>
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Received on Fri Oct 21 2016 - 07:30:04 PDT
