Dear Elaine, thank you so much because i understand my mistakes, but i'm afraid i have to ask you something again. I've done as you said, so i selected the residues and then used join models function but the apply button cannot be clicked. I don't understand if this happens because:

-of the selected residues
-the 2 proteins have to be already in position for the bond
-something to be done before using join models

I'm sorry to trouble you so much
Sincererly

Mahad

2013/1/25 Elaine Meng <meng@cgl.ucsf.edu>
Hi Mahad,
If I read your mail correctly, there is no overlap between the two sequences.  You would only use "match" to overlap structures, i.e. to try to put one group of atoms on top of another group of atoms (with exactly the same number of atoms).  As the error message said,

> match #0:422 #1:442
> Unequal numbers of atoms chosen for evaluation

... residue 422 in #0 and residue 442 in #1 do not have the same numbers of atoms, which is not surprising if one is an "R" and the other is "D." You could specify using backbone atoms only to get the same numbers, for example:

match #0:422@n,ca,c,o #1:442@n,ca,c,o

HOWEVER: from your description it sounds like you do not really want to match (put 422 on top of 442), but instead you want to join the two peptides (add peptide bond between 422 and 442).  In that case you should use the Build Structure tool (in menu under Tools... Structure Editing), Join Models section.

<http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/editing/editing.html>
<http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/editing/editing.html#join>

First select the two atoms you want to bond, maybe something like this:

select #0:422@c #1:442@n

... and then use the C-N peptide bond option in Join Models.
I hope this helps,
Elaine
-----
Elaine C. Meng, Ph.D.
UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab
Department of Pharmaceutical Chemistry
University of California, San Francisco

On Jan 25, 2013, at 6:57 AM, mahad iou muddei addò wrote:

> Hi, i'm working with chimera for the first time. I need to patch 2 structures that i have the PDBs. I've already read the user guide and try to follow the instructions for making a controlled superimposition of the two structures.
> These are my two sequence:
>
> 1)RKYVYSLYWSTLTLTTIGETPPPVRDSEYFFVVADFLIGVLIFATIVGNIGSMISNMNAARAEFQARIDAIKQYMHFR
>
> 2)DSSRRQYQEKYKQVEQYMSFHKLPADFRQKIHDYYEHRYQG-KMFDEDSILGELNGPLREKIVNFNCRKLVASMPLFANADPNFVTAMLTKLKFEVFQP
> GDYIIREGTIGKKMYFIQHGVVSVLTK-NKEM--KLSDGSYFGEICLLT------RGRRTASVRADTYCRLYSLSVDN
> FNEVLEEYPMMRRAFETVAIDRLDR/
>
> I need to create a structure like this:
>
> RKYVYSLYWSTLTLTTIGETPPPVRDSEYFFVVADFLIGVLIFATIVGNIGSMISNMNAARAEFQARIDAIKQYMHFRDSSRRQYQEKYKQVEQYMSFH
> KLPADFRQKIHDYYEHRYQG-KMFDEDSILGELNGPLREKIVNFNCRKLVASMPLFANADPNFVTAMLTKLKFEVFQP
> GDYIIREGTIGKKMYFIQHGVVSVLTK-NKEM--KLSDGSYFGEICLLT------RGRRTASVRADTYCRLYSLSVDN
> FNEVLEEYPMMRRAFETVAIDRLDR/
>
> I know the position of the aa involved but after i launch the command trough command line it gives me errors like
>
> match #0:422 #1:442
> Unequal numbers of atoms chosen for evalutation
>
> What am i doing wrong?
> Thanks, sincererly
>
> Mahad