Perhaps the subunits have different conformational states that are differently able to bind the ligand. There are definitely oligomers where the subunits do that e.g. mGluR1 binding domain dimer is usually 1 open subunit and 1 closed in the active state without cations at the interface. This is seen in both crystal structures of the isolated domain and FRET studies of whole receptors in cells.
Best wishes James > On 5 Mar 2022, at 20:01, <Shymaa Damfo> <shymaa.damfo...@ucl.ac.uk> wrote: > > Hello all, > > In homo-dimeric or homo-oligomeric protein crystal structures, what would be > the reason for having a ligand (chemical compound or fragment) binds to one > molecule and not all molecules in the asymmetric unit? > > I have soaked a fragment that has an affinity of 200 uM to a viral protein > but I can only see it binds to one molecule (we have eight molecules in the > AU). This is was also notable as well in some published PDB (dimeric protein). > > Any suggestions? > > Best wishes, > Shymaa > > ######################################################################## > > To unsubscribe from the CCP4BB list, click the following link: > https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fcgi-bin%2FWA-JISC.exe%3FSUBED1%3DCCP4BB%26A%3D1&data=04%7C01%7Ckriegerj%40PITT.EDU%7Ced7f4a91684648454d9608d9fee2f663%7C9ef9f489e0a04eeb87cc3a526112fd0d%7C1%7C0%7C637821073030033669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=cvfrwlylIMgKRx%2FqLdaPD3L1ksbjl%2B0EJJVReJHooQ8%3D&reserved=0 > > This message was issued to members of > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.jiscmail.ac.uk%2FCCP4BB&data=04%7C01%7Ckriegerj%40PITT.EDU%7Ced7f4a91684648454d9608d9fee2f663%7C9ef9f489e0a04eeb87cc3a526112fd0d%7C1%7C0%7C637821073030033669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=u5dnPAFTmLiOMhSdvPY96T1W1hHVU4VuR6zl9CcyoU8%3D&reserved=0, > a mailing list hosted by > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.jiscmail.ac.uk%2F&data=04%7C01%7Ckriegerj%40PITT.EDU%7Ced7f4a91684648454d9608d9fee2f663%7C9ef9f489e0a04eeb87cc3a526112fd0d%7C1%7C0%7C637821073030033669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=nPuFjKYokj5D0%2B8HbzJ4CmoF3I0jJyF%2Foyq9gyEcmn8%3D&reserved=0, > terms & conditions are available at > https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.jiscmail.ac.uk%2Fpolicyandsecurity%2F&data=04%7C01%7Ckriegerj%40PITT.EDU%7Ced7f4a91684648454d9608d9fee2f663%7C9ef9f489e0a04eeb87cc3a526112fd0d%7C1%7C0%7C637821073030033669%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=i3n7vZg%2BAVSs1l5jgnx1heEPFjwnQFhuIiZ1zMe%2FCu8%3D&reserved=0 ######################################################################## 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/
