[gmx-users] zinc force field parameters

[jozef hritz]

I have protein containning four-coordinated zinc atom, between one HIS and
three CYS. Distance between ZN and N of HIS is 2.0 A and distance between
ZN and S of CYS is 2.3 A. I would like to ask You for advice: What charges
should be used for ZN, N (HIS), S (CYS) in such system?
I Gromacs force field is as default charge of ZN +2, but I think it's too
much when it's coordinated in protein. Has someone experience with metals
coordinated in proteins?

	Thanks
								Jozef

PS: Can You recomend me some linux program for easy manual(by eyes) puting
of ligand to protein. Thanks