Hi Rohit Since you are saying the C terminus in crystal structure is not end of your protein in crystal, and you are worried about its charge status, is in't a good idea to model few residues beyond the C terminus you see in crystal structure using weak electron density and crystal packing as guide and then do the electrostatic calculation. Even if you are modeling it as COOH, it's not going to be true end anyway. Two or three extra residues should be sufficient as ionic interaction is going to be quite weak beyond 8-10 A.
Dhiraj ________________________________ From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> on behalf of rohit kumar <rohit...@gmail.com> Sent: Wednesday, September 22, 2021 4:29 PM To: CCP4BB@JISCMAIL.AC.UK <CCP4BB@JISCMAIL.AC.UK> Subject: [External] [ccp4bb] Protein's C-terminal neutral Hello Everyone, Is there any way that I could make my protein's C-terminal neutral using Coot? Actually, I have a protein-peptide complex structure and my peptide is bound at the C-terminal end. While making a surface charge diagram it is negatively charged (because of the CO group at the end, which is not the end residue of my purified protein) and I want to make it neutral (possibly a peptide bond in solution). Please let me know if I am clear enough with my question. Thank you -- Regards Dr. Rohit Kumar Singh Postdoctoral fellow Aurora CO USA ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/