Dear all,
I am refining a model based on a 4.3A EM density map,and there are some cis-peptides in the beginning model.
By using phenix.real_space_refine with a very low cis-peptide threshold (0), all the cis-peptide become to the twisted.
The start Omega angle:
cis-proline: 31.63 %
twisted proline: 0.00 %
cis-general: 11.11 %
twisted-general: 0.05 %
The final Omega angle:
cis-proline: 0.00 %
twisted proline: 27.55 %
cis-general: 0.00 %
twisted-general: 6.04 %
My questions are:
1) What is the twisted peptide?
2) Is the amount acceptable at the current resolution?
2) How to refine it?
Thanks in advance!
Yang Shi
