Dear CCP4 BB,
We solved one co-crystal structure of a protein and a compound. We found this compound could covalently modify an asparate residue of this protein. A covalent bond formed between a oxygen atom of Asp carboxyl group and a carbon atom of that compound. Does anyone knows how to draw a covalent bond between the oxygen atom and the carbon atom and refined it? We tried coot, pymol and chimera, but failed. Thank you in advance! Best regards, Jiyong Su