[Ifeffit] Atoms restraints

[Massimiliano Stola]

Hi,

I'm a new user of the Feffit package and I have a question about atom 
restraints for the fitting.

I'm dealing with metal binding protein, and somehow I need to keep some atoms 
in a fixed structure (mainly histidine rings) while leaving a certain degree 
of freedom to the remaining atoms of the environment.

I'd like to know if there is a library containing histidine structure 
restraints or if exists any input file of a similar matter.

Looking forward to hearing from you
Max