The protein-protein interaction map of Helicobacter pylori

With the availability of complete DNA sequences for many prokaryotic and eu karyotic genomes, and soon for the human genome itself, it is important to develop reliable proteome-wide approaches for a better understanding of pro tein function(1). As elementary constituents of cellular protein complexes and pathways, protein-protein interactions are key determinants of protein function. Here we have built a large-scale protein-protein interaction map of the human gastric pathogen Helicobacter pylori. We have used a high-thro ughput strategy of the yeast two-hybrid assay to screen 261 H. pylori prote ins against a highly complex library of genome-encoded polypeptides(2). Ove r 1,200 interactions were identired between H. pylori proteins, connecting 46.6% of the proteome. The determination of a reliability score for every s ingle protein-protein interaction and the identification of the actual inte racting domains permitted the assignment of unannotated proteins to biologi cal pathways.