COGNAC users have the choice of providing three types of input for searching:

      Please select one of the search options below:
Option 1: Allows a user to search a database of PDB sourced structures for hydrogen bonded base interactions from base pairs to formations containing as many as six bases.
       Search RNA Structures in the PDB
Option 2: A user with an RNA structure of interest can opt to upload the structure and then annotate the structure for all possible hydrogen bonded base interactions.
       Upload a RNA Structure (PDB file):
Option 3: A user can opt to compare the COGNAC hydrogen bonded interactions annotations for two different but closely related structures - such as between mutants or structures that are bound and unbound to ligands.
      Compare hits for two RNA Structures

Structure 1:
Structure 2: