Ribbon diagram of human <a href="https://en.wikipedia.org/wiki/cathepsin_K" class="extiw" title="w:cathepsin K">cathepsin K</a>, colored by <a href="https://en.wikipedia.org/wiki/secondary_structure" class="extiw" title="w:secondary structure">secondary structure</a>.<br>Created using <a rel="nofollow" class="external text" href="http://www.accelrys.com/products/downloads/ds_visualizer/index.html">Accelrys DS Visualizer Pro 1.6</a> and <a href="https://en.wikipedia.org/wiki/GIMP" class="extiw" title="w:GIMP">GIMP</a>.
<a href="//commons.wikimedia.org/wiki/User:Fvasconcellos" title="User:Fvasconcellos">User:Fvasconcellos</a>
From <a href="https://en.wikipedia.org/wiki/Protein_Data_Bank" class="extiw" title="w:Protein Data Bank">PDB</a> entry <a rel="nofollow" class="external text" href="http://www.rcsb.org/pdb/cgi/explore.cgi?pdbId=1TU6">1TU6</a>.