Answers.Body: <p>In cases when you cannot find answer through the web interface, you can <a href="http://www.wwpdb.org/download/downloads" rel="nofollow noreferrer">download all the data</a> and search it locally.</p>
  
  <p>Relying on the PDB annotations of SS bonds, you could search for PDB files that have exactly one SSBOND record:</p>
  
  <pre><code><span class="math-container">$ cd $</span>PDB_DIR/structures/divided/pdb/
  <span class="math-container">$ zgrep -c ^SSBOND aa/pdb*.ent.gz | grep :1$</span>
  aa/pdb2aaq.ent.gz:1
  aa/pdb3aad.ent.gz:1
  aa/pdb5aap.ent.gz:1
  aa/pdb6aa4.ent.gz:1
  aa/pdb6aa5.ent.gz:1
  </code></pre>
  
  <p>All PDB files (gzipped) take about 30GB of disk space.</p>
  
  <p>The caveat is that some entries are available only in the mmCIF format. Using mmCIF would be slighty more complex: you would need to count <code>_struct_conn.conn_type_id</code> being <code>disulf</code>. And you would need to download 10GB more.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-04-18T09:56:06.620Z
Answers.Text: Thanks! I need just a few examples, to the 1st method is perfect!
Answers.UserDisplayName: Jake B.
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Body: <p>I would like to find proteins with exactly one SS bond. Is there a database where I can search this? I've tried advanced search on <a href="https://www.rcsb.org/" rel="nofollow noreferrer">https://www.rcsb.org/</a>, but no such option, at least I could not find it.</p>
  
Tags: <public-databases><protein-structure>
Title: Proteins with one SS bond?
ThreadText: # Proteins with one SS bond?
  
  (Asked by: username_0 on 2019-04-18)
  
  I would like to find proteins with exactly one SS bond. Is there a database where I can search this? I've tried advanced search on <https://www.rcsb.org/>, but no such option, at least I could not find it.
  
  **Tags:** public-databases, protein-structure
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-04-18. Score: 3 | Accepted answer
  
  In cases when you cannot find answer through the web interface, you can [download all the data](http://www.wwpdb.org/download/downloads) and search it locally.
  
  Relying on the PDB annotations of SS bonds, you could search for PDB files that have exactly one SSBOND record:
  
  ```
  $ cd $PDB_DIR/structures/divided/pdb/
  $ zgrep -c ^SSBOND aa/pdb*.ent.gz | grep :1$
  aa/pdb2aaq.ent.gz:1
  aa/pdb3aad.ent.gz:1
  aa/pdb5aap.ent.gz:1
  aa/pdb6aa4.ent.gz:1
  aa/pdb6aa5.ent.gz:1
  
  ```
  
  All PDB files (gzipped) take about 30GB of disk space.
  
  The caveat is that some entries are available only in the mmCIF format. Using mmCIF would be slighty more complex: you would need to count `_struct_conn.conn_type_id` being `disulf`. And you would need to download 10GB more.
  
  > **Comments:**
  > **username_0**: Thanks! I need just a few examples, to the 1st method is perfect!  
  
  ---
  
  