Use match-&gt; align to get a structural superposition and sequence alignment, then set your alignment type to AL2CO. Go to render by attribute and then hit the select by attribute tab. Select the range from 0-whatever your maximum is. Should be around 4 if you&#39;ve got any conserved tryptophans. That will select all invariant residues. <br><br>Jean-Paul Boissel &lt;boissel@uni-mainz.de&gt; wrote:<br><br><div>Hi,&nbsp;</div><div><br></div><div>By homology modelling, I got putative structures for five closely related amino acid transporters. &nbsp;Is there any script that will allow the quick selection and visualisation of the invariant residues on the structures?</div><div>Thanks,</div><div><br></div><div>Jean-Paul</div><div><br></div><div>&nbsp;</div>