[gmx-users] How to choose bd_fric value in brownian dynamics

[Mohan maruthi sena]

Hi all,
         I want to perform brownian dynamics simulations  using gromacs
4.5.5 for  a system containing  protein in water. What is the basis to
select the bd_fric value for this system.  I came to know through previous
posts that a value of 3000 would be fine for a time step less than 4fs. My
question is on what basis we choose the value for bd_fric ? How does high
bd_fric value impact  a simulation when compared to slow bd_fric value ?


Thanks for  a reply in advance,
Mohan