The goal of this project is to develop solutions to enhance interoperability between bioinformatics applications. Most existing applications adopt different data formats, forcing biologists into tedious translation work. We propose to use of Nexus as an intermediate representation language. We develop a complete grammar for Nexus and we adopt this grammar to build a parser. The construction heavily relies on the peculiar features of Prolog, to easily derive effective parsing and translating procedures. We also develop a general parse tree format suitable for interconversion between Nexus andot her formats.