a, b, Fraction of PPIs with N or C terminus <10 Å (a) or <20 Å (b) to PPI interface, for PPIs with known structure in and not in HuRI (n = 37–1,891 PPIs). Error bars are standard error of proportion. The structure of UBE2D3 bound to RNF115 illustrates an example of a PPI found only by Y2H assay version 3 (PDB code 5ULH). c, MAPPIT recovery rates of HuRI and Lit-BM PPIs that were also detected in HuRI by the number of screens each pair was detected in. Error bars are 68.3% Bayesian confidence interval (n = 22–793 PPIs successfully tested in each category). d, MAPPIT recovery rates of Lit-BM PPIs that were also detected in HuRI, for increasing number of pieces of experimental evidence per PPI. Error bars are 68.3% Bayesian confidence interval (n = 24–61 PPIs successfully tested in each category). e, f, Distributions of interaction interface area (e) or number of atomic contacts (f) by the number of HuRI screens in which a PPI is detected, with box plots showing median, interquartile range (IQR), and 1.5× IQR (with outliers); n = 1,004 PPIs. g, Left, examples of within-complex interactions detected in HuRI (purple) and BioPlex (orange). Right, fraction of HuRI PPIs between proteins of protein complexes that link proteins of the same complex, split by PPIs found in single and multiple screens (dark purple). Error bars are standard error of proportion; n = 1,042 and 775 PPIs, for single and multiple screens, respectively. h, Number of screens each PPI in HuRI was detected in, split by Y2H assay version. i, Number of Y2H assay versions each PPI in HuRI was detected in. j, Estimates of the size of the total binary protein interactome and the fraction covered by HuRI, right and left, respectively, as a function of the minimum number of publications per gene and the minimum number of evidence for the Lit-BM reference. Error bands are 68.3% Bayesian confidence interval; n ≥ 170 Lit-BM PPIs.