Bipartite graph representation of proteins and domains. (A) An example of a subgraph of metabolic enzymes and their constituent domains. Nodes correspond to proteins and domains. Edges connect proteins to their constituent domains. In bold is a biclique with five proteins and four domains. The biclique's proteins include acetyl-CoA carboxylase, pyruvate carboxylase 1 and 2, urea amidolyase and HFA1 (SwissProt IDs YNR016C, YGL062W, YBR218C, YBR208C and YMR207C). The proteins share four domains: Carbamoyl-phosphate synthase L chain, Carbamoyl-phosphate synthetase large chain N-terminal, Biotin carboxylase C-terminal and Biotin/lipoyl attachment (Interpro IDs IPR005479, IPR005481, IPR005482 and IPR000089). (B) Distribution of number of proteins per domain in the data. Regression line parameters: f(x) = -1.74x + 2.7 (linear fit model p < 0.0001). (C) Correlation between domain and protein degrees. For each degree of a protein, ranging from 1 to 7, the mean degree of domains comprising these proteins was calculated. Regression line parameters are f(x) = 0.8x + 0.96 (linear fit model p < 0.0327).