AMBER Archive (2003)

Subject: decrease a force const. for angle

From: Michal Otyepka (otyepka_at_aix.upol.cz)
Date: Mon Feb 10 2003 - 06:47:35 CST

Dear AMBERs,

I wonder if it is possible to easy decrease a force constant for agle
A-B-C for a general amino acid. I would like to decreace a angle bending
term Ca-Cb-Cg for only one res. The parm96 applies for the angle 63.0 f.c.
but i want to use lower f.c. (only for one agle in the protein). One way
how to do it is to creare new residue with modified a. types and to modify
ff. But can I use e.g. restraint (??with negative sign??) in sander input
file????? In case I define a restraint for Ca-Cb-Cg bond this restraint
replaces force constant defined by the FF? or the result is the sum of
restraint and force constant defined by FF? Could anybody provide me by an
example for such &rst section?

Many thank in advance for your help.

Michal Otyepka

      
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