That looks like an error on the web page.  It should be label_asym_id.  If it is auth_aysm_id, then we are all screwed. The auth_asym_id should match what whatever the author considered a chain in the publication about the structure.  The label_asym_id is needed for referential consistency between the various mmCIF tables.     -- Greg On 12/4/2020 10:55 AM, Tristan Croll wrote: > No - they're changing the auth_asym_id. See > https://www.wwpdb.org/documentation/carbohydrate-remediation > <https://www.wwpdb.org/documentation/carbohydrate-remediation>: > > Oligosaccharide molecules are classified as a new entity type, > branched, assigned a unique chain ID (_atom_site.auth_asym_id) and a > new mmCIF category introduced to define the type of branching > (_pdbx_entity_branch.type) . > wwPDB: <https://www.wwpdb.org/documentation/carbohydrate-remediation> > wwPDB: Worldwide Protein Data Bank. Carbohydrate Remediation. As the > PDB archive grows, and the related science and techniques evolve, the > 3D structures represented in the Core Archive require ongoing > improvement ("remediation") to ensure consistency, accuracy, and > overall quality. > www.wwpdb.org > > > ------------------------------------------------------------------------ > *From:* Greg Couch <gregc@cgl.ucsf.edu> > *Sent:* 04 December 2020 18:51 > *To:* Luca Jovine <luca.jovine@ki.se>; Mailing List CCP4 > <CCP4BB@jiscmail.ac.uk>; Mailing List PDB, <pdb-l@sdsc.edu> > *Cc:* Tristan Croll <tic20@cam.ac.uk> > *Subject:* pdb-l: Re: [ccp4bb] Coming July 29: Improved Carbohydrate > Data at the PDB -- N-glycans are now separate chains if more than one > residue > mmCIF has two different chain ids. One the the label_asym_id which is > used for internal consistency with the entities.  The other is the > auth_asym_id which is whatever the author chooses. If the glycans are > separate entities, then the label_asym_id HAS to be different for each > instance of an entity.  But the auth_asym_id could be the same for all > covalently bonded units. > > In ChimeraX, we use the label_seq_id for the chain id when constructing > the molecule and we use the auth_asym_id for the chain id in the user > interface. > >      -- Greg >