In January 10 Nature, two groups report large-scale proteomic projects designed to analyze protein complexes in the budding yeast Saccharomycescerevisiae. Anne-Claude Gavin and researchers at the German company Cellzome used a tandem-affinity purification, 'TAP tagging', methodology to isolate protein complexes for subsequent mass spectrometry analysis (Nature 2002, 415:141-147).

Analysis of 1,739 tagged genes lead them to the identification of 98 known nonredundant multiprotein complexes and 134 new complexes. They found partners for 78% of proteins and isolated complexes containing from 2 to 83 components (with an average of 12 per complex). Using a similar approach, Yuen Ho and researchers at the Canadian company MDS Proteomics began with 725 carefully chosen yeast bait proteins tagged with a Flag epitope (Nature 2002, 415:180-183). They identified 1,578 interacting proteins, representing 25% of the proteome. Both groups report novel features of protein complexes involved in the...