Fig. 3From: The protein-protein interaction ontology: for better representing and capturing the biological context of protein interactionThe hierarchical structure and glossary of PPIO. (A) The hierarchical structure of PPIO. (B) The glossary of PPIO terms. The open-source ontology editor OBO-Edit (version 2.3.1) was used to display the PPIO hierarchical tree and term glossaryBack to article page