Dear all,

I am trying to pull a short peptide from another peptide by slowly increasing the distance between them. To this end, I translate an atom by @VALX @VALY @VALZ and constrain this atom in space and then minimize

----
coordinate trans XDIR @VALX YDIR @VALY ZDIR @VALZ -
select atom pept 15 CA end

constrain harmonic expo 2 force 5 -
select segid pept .and. resid 15 .and. type CA end
----

It seems that doing the same but by using the COMP coordinate set does not end with the same minimized geometry. Actually is there a difference in using the following:

----
coor copy COMP

coordinate COMP trans XDIR @VALX YDIR @VALY ZDIR @VALZ -
select atom pept 15 CA end

constrain COMP harmonic expo 2 force 5 -
select segid pept .and. resid 15 .and. type CA end
----

and then minimize?
Actually is the program using the same "reference coordinates" in both case (without and with using COMP in the script)?

Thank you very much in advance for any answers.
Best,
Fabrice.