The Protein Structure Viewer module displays a NGL Viewer rendering of PDB structures of Papillomavirus proteins. The structure viewer can be accessed in several ways. A list of available structures can be browsed in the Table of available PV protein structures. Alternatively, the Search Module can be used to retrieve proteins with associated structures in either the Protein Sequences or Structures in PDB databases. Proteins with a known structure are indicated by a . Clicking this icon will display this protein in the Structure Viewer. In the Protein Sequences database, many proteins have a homologous structure indicated by a light orange icon . Accessing the Structure Viewer through this icon will display the known structure of a homologous protein and a pairwise alignment of both proteins. This allows users to identify regions of sequence similarity or divergence on the protein structure.