Hi, at 2A resolution you do not need to do group B refinement. You might find this helpful in understanding some things about B-factor refinement (pages 24-31): http://www.phenix-online.org/newsletter/CCN_2010_07.pdf Pavel. On 7/16/10 6:30 PM, hongjunyu wrote: > Dear Fred. and Martyn: > Thank you for your replies. I am new to CNS and I just followed the CNS > website protocols. I got your ideas. Since my resolution is 2A, I should skip > the bgroup refinement. > > Hongjun Yu