id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	blockedby	blocking	notify_on_close	platform	project
19367	Replace RCSB ligand-expo URL which is being retired.	Tom Goddard	Greg Couch	"The Ligand Expo RCSB site is being retired and the following URL will cease to work at some point

    http://ligand-expo.rcsb.org/

The new URL to fetch a ligand .cif file is

    https://files.rcsb.org/ligands/download/HEM.cif

ChimeraX is using this in the mmcif reader in mmcif.pyx _get_template(). This should be fixed for the ChimeraX 1.11 release.

This was reported by Brinda Vallat and Ezra Peisach:

On 11/13/25 9:07 AM, Brinda Vallat wrote:
Hi Tom, 

Ezra (cc'd here) has pointed out that there are some references to ligand expo in ChimeraX. 

We want to inform you that ligand expo is being shutdown. Please check to make sure that any old references are taken care of. 

Please let us know if you have any questions. 

Thank you,
Brinda


--
BRINDA VALLAT, Ph.D.
RCSB PDB

----

From: Ezra Peisach
Subject: Re: Ligand-expo to be shutdown
Date: November 13, 2025 at 6:47:58 AM PST
To: Brinda Vallat, Tom Goddard

For further details..

I noticed that you have a shared library that references ligand-expo. The centos-7 version of ChimeraX had a python module which performed downloads from there

% strings ./usr/libexec/UCSF-ChimeraX/lib/python3.11/site-packages/chimerax/mmcif/mmcif.cpython-311-x86_64-linux-gnu.so | grep ligand-ex
http://ligand-expo.rcsb.org/

If you are still downloading from ligand-expo, I suggest a changed the the RCSB PDB download API such as:

https://files.rcsb.org/ligands/download/HEM.cif

Thank you very much,

Ezra Peisach



"	defect	assigned	moderate	1.12	Input/Output				brinda.vallat@… ezra.peisach@… Eric Pettersen tcroll@…				all	ChimeraX