Scientists working as part of a multi-investigator ENIGMA (Ecosystems & Networks Integrated with Genes and Molecular Assemblies Scientific Focus Area) project have determined that protein-protein interactions occur more frequently among proteins with similar functions. The team of researchers, led by Gareth Butland in the Environmental Genomics & Systems Biology Division, used high throughput functional genomics to study the protein-protein interactome of the model sulfate reducing bacterium Desulfovibrio vulgaris Hildenborough. Their findings critically re-evaluate published bacterial interaction networks and establish benchmarks for high confidence protein interactomes. The manuscript can be found online at Molecular and Cellular Proteomics.