AMBER Archive (2005)

Subject: AMBER: peptide side chain modification with LEAP

From: Hannes Barsch (hbarsch_at_physik.uni-bielefeld.de)
Date: Tue Apr 12 2005 - 09:19:53 CDT


I try to use LEAP to set up an oligopeptide with a dye labelled lysine
within. I already set up prep and frcmod files for the dye using
Antechamber, successfully. Using the dye's library for a sequential peptide,
i.e. having the dye attached at the N terminus of the peptide works fine.
(Using pep = sequence {DYE PRO LYS ...})

Now I need the dye to be attached to the free amino butyl side chain of
lysine. Using teLeap I set up the peptide using the sequence command. With
"deleteBond" and "remove" I got rid of one of the amino group's hydrogens.
The thing to do would be to import my dye as a residue into the molecule and
connect the cabonyl C of the dye to the lysine's amino N. If I use xLeap
there is a menu entry "Unit --> Import Unit" where I can import a residue
but I have not figuered out, yet, how to do the same in teLeap.

If I try to add the dye as a residue
>add pep dye.1
        ^ ^
        | |
        | residue of the dye contained by the unit dye
        unit containing the peptide
this results in an error:
  add: The object dye.1 is already contained within

So how can I get that residue out of its box? Or how can I import a whole
unit into another unit's residue?
Thanks for any hints!

Regards,

Hannes

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