<p>I'm not sure about the RCSB, but you can get such a list from the PDBe REST API, as documented in the <a href="http://www.ebi.ac.uk/pdbe/api/doc/compounds.html" rel="nofollow noreferrer">compounds section</a>:</p>

<p><a href="http://www.ebi.ac.uk/pdbe/api/pdb/compound/in_pdb/ADN" rel="nofollow noreferrer">http://www.ebi.ac.uk/pdbe/api/pdb/compound/in_pdb/ADN</a></p>

<p>Alternatively, from an older service:</p>

<p><a href="http://www.ebi.ac.uk/pdbe-srv/pdbechem/PDBEntry/download/ADN" rel="nofollow noreferrer">http://www.ebi.ac.uk/pdbe-srv/pdbechem/PDBEntry/download/ADN</a></p>

CC BY-SA 4.0
2018-06-14T16:30:33.723Z
2018-06-14T16:30:33.723Z
marcin
<p>If you're looking at the entry for a ligand, for example, <a href="http://www.rcsb.org/ligand/ADN" rel="nofollow noreferrer">adenosine</a>, there's a link on the webpage to entries for which this entry exists as a free ligand. 
However, I want to access this via the API and can't seem to find docs/info on how to do that. </p>

<p>I have been looking at the fields you can use to get <a href="https://www.rcsb.org/pdb/results/reportField.do" rel="nofollow noreferrer">custom reports</a>.  </p>

<pdb>
Can you query the RCSB PDB API with a ligand and return the IDs of all entries in which it appears as a free ligand?
# Can you query the RCSB PDB API with a ligand and return the IDs of all entries in which it appears as a free ligand?

(Asked by: username_0 on 2018-06-14)

If you're looking at the entry for a ligand, for example, [adenosine](http://www.rcsb.org/ligand/ADN), there's a link on the webpage to entries for which this entry exists as a free ligand.
However, I want to access this via the API and can't seem to find docs/info on how to do that.

I have been looking at the fields you can use to get [custom reports](https://www.rcsb.org/pdb/results/reportField.do).

**Tags:** pdb

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## 1 answers

### Answer by username_1 on 2018-06-14. Score: 2

I'm not sure about the RCSB, but you can get such a list from the PDBe REST API, as documented in the [compounds section](http://www.ebi.ac.uk/pdbe/api/doc/compounds.html):

<http://www.ebi.ac.uk/pdbe/api/pdb/compound/in_pdb/ADN>

Alternatively, from an older service:

<http://www.ebi.ac.uk/pdbe-srv/pdbechem/PDBEntry/download/ADN>


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