-read from PDB will be processed to derive secondary structure annotation.
-<p><em>Use RNAView for secondary structure</em> - if selected, the RNAView service will be
-automatically called to derive secondary structure information.
-<p><em>Add secondary structure annotation to alignment</em> - if selected, PDB secondary structure
-annotation will be shown on the alignment when available.
-<p><em>Add Temperature Factor annotation to alignment</em> - if selected, PDB Temperature Factor
-annotation will be shown on the alignment when available.
+read from PDB will be processed and annotation added to associated sequences.
+<p><em>Use RNAView for secondary structure</em> - if selected, the pyRNA RNAView service (<a href="https://github.com/fjossinet/PyRNA">https://github.com/fjossinet/PyRNA</a>) will be
+called to derive secondary structure information for RNA chains.
+<p><em>Add secondary structure annotation to alignment</em> - if selected, <a href="http://swift.cmbi.ru.nl/gv/dssp/">Jmol's implementation DSSP</a> will be used to add annotation to polypeptide chains in the structure.
+<p><em>Add Temperature Factor annotation to alignment</em> - if selected, values extracted from the Temperature Factor
+column for the backbone atoms in the PDB file will be extracted as annotation lines shown on the alignment.