﻿id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	blockedby	blocking	notify_on_close	platform	project
6067	Update RCSB biounit fetch to new URLs if needed	Tom Goddard	Tom Goddard	"The RCSB is updating their mmCIF assembly files and changing the ftp site for fetching them in May 2022.  The assembly files will also contain multiple chains instead of multiple models.

We need to verify that the ChimeraX (and Chimera) will still work with the URL changes.

We need to make sure the NIAID scripts that use fetched biounit files still work.



Begin forwarded message:

From: Jasmine Young <jasmin@rcsb.rutgers.edu>
Subject: pdb-l: Distributing PDBx/mmCIF Formatted Assembly Files
Date: February 2, 2022 at 6:59:30 AM PST
To: pdb-l@lists.wwpdb.org

Dear PDB users,

Starting May 3, 2022, the PDB archive will distribute assembly files in PDBx/mmCIF format, allowing direct access and visualization of the curated assemblies for all PDB entries.

Currently, PDBx/mmCIF formatted assembly files are provided for structures that are non-PDB compliant, however the coordinates use model numbers to differentiate alternate symmetry copies of PDB chain IDs. This method is not ideal, nor necessary, for the current archive PDBx/mmCIF format and has lead to limited use of these files in community software tools. In response to this issue and recommendations by the wwPDB advisory committee, we are implementing updated, standardized practices for generation of assembly files for all PDB entries.

These updated PDBx/mmCIF format assembly files will have improved organization of assembly data to support usage by the community. These files will include all symmetry generated copies of each chain within a single model, with distinct chain IDs (_atom_site.auth_asym_id and _atom_site.label_asym_id) assigned to each. Generation of distinct chain IDs in assembly files are based upon the following rules:

# Chain IDs of the original chains from the atomic coordinate file will be retained (e.g., A)
# Assign unique chain ID (atom_site.label_asym_id and atom_site.auth_asym_id) for each symmetry copy within a single model. Rules of chain ID assignments:

* The applied index of the symmetry operator
  (pdbx_struct_oper_list.id) will be appended to the original chain ID
  separated by a dash (e.g., A-2, A-3, etc.)
* If there are more than one type of symmetry operators applied to
  generate symmetry copy, a dash sign will be used between two
  operators (e.g., A-12-60, A-60-88, etc.)

In addition, entity ID and chain ID mapping categories will be provided: _pdbx_entity_remapping and _pdbx_chain_remapping.

A new directory (ftp.wwpdb.org/pub/pdb/data/assemblies/mmCIF/) will be created for the distribution of these updated assembly files. The directory containing the existing assembly mmCIF files for large entries will be removed (ftp.wwpdb.org/pub/pdb/data/biounit/mmCIF/ <https://ftp.wwpdb.org/pub/pdb/data/biounit/mmCIF/>).

wwPDB asks all PDB users and software developers to review code and address any limitations related to PDB assemblies. Sample files are made available for testing purposes and to support community adoption at GitHub.com/wwpdb/assembly-mmcif-examples (https://github.com/wwpdb/assembly-mmcif-examples).

If you plan to use these assembly files for graphical viewing, check if your visualization software (e.g., PyMol, ChimeraX, etc.) supports instantiation of assemblies directly from atomic coordinate files (_struct_assembly related categories), you do so for improved efficiency.

For any further information please email info@wwpdb.org.


-- 
Regards,

Jasmine

===========================================================
Jasmine Young, Ph.D.
Biocuration Team Lead
RCSB Protein Data Bank
Research Professor
Institute for Quantitative Biomedicine
Rutgers, The State University of New Jersey
174 Frelinghuysen Rd
Piscataway, NJ 08854-8087

Email:jasmine@rcsb.rutgers.edu
Phone: (848)445-0103 ext 4920
Fax: (732)445-4320
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and follow the instructions in the newly received email."	defect	closed	moderate	1.4	Core		fixed		Eric Pettersen				all	ChimeraX
