[Chimera-users] large datasets

Elaine Meng meng at cgl.ucsf.edu
Fri Jul 7 08:16:06 PDT 2017

Hi Arthur,
It’s mostly impossible to answer without knowing the model number and chain IDs.  Also if you say the structures are still there, you were not really deleting them, you were only hiding them.

To delete you can use the command “delete” with a specification of which atoms to delete.  The “atom specification” page explains how to specify chain ID, etc. in commands.

Here is one simple example to delete chains A-C and F:

delete :.a-c:.f

Or, if you can select all the parts you want to delete, you can then use command “delete sel” or menu: Actions… Atoms/Bonds… delete.  If it is easier to select the parts you want to keep, then do that first, but then use the Select menu to invert the selection to make it the parts you want to delete.

One way to see what chains you have is to look in the Select… Chain menu, and you can even use it to highlight each chain and see where in the structure it is.

I hope this helps,
Elaine C. Meng, Ph.D.                       
UCSF Chimera(X) team
Department of Pharmaceutical Chemistry
University of California, San Francisco

> On Jul 7, 2017, at 6:37 AM, Arthur Szabo <agszabo at outlook.com> wrote:
> I am trying to work with a data set that has three copies of a protein complex per asymetric unit in the cell. It is a rather large complex. I can delete  two of the copies and work with only one complex.
> There are 9 chains in each complex. 3 oligonucleotide sequences, and  6 proteins of different sizes, the largest having about 1400 residues.
> The way in which I  selected only one complex to visualize was to delete  the other 18 chains one at a time.  There must be a way of deleting each of the other two copies all at once but I did not try to find  it in the Chimera tutorial list.
> The deletion only eliminates the image of each complex. Both complexes are still there in the total data set. The result  is that saving a session takes about three minutes because it saving all the coordinates of the three copies of the complex.
> How can I make  the process more efficient and delete two copies from the coordinate data set.
> Thank you
> Arthur G. Szabo

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