Dali Z-scores of SNs of a representative set of SCOP structures plotted against their FS values. The diagram shows in a quantitative way how structure similarity translates to similarity of function. In order to characterize the function-structure relation, all data points were grouped into semantic similarity bins and box-plotted. Box whiskers denote 0.05 and 0.95 quantiles; box edges and the intersecting line are 0.25, 0.75 and 0.5 quantiles respectively; the average values of Z-scores are shown by squares; minimal and maximal values are marked with crosses. The width of each bin was 0.02. The experiment showed that functional and structural similarities are inter-dependent for proteins whose functional similarities are higher than ca. 0.6 . Red line marks the 0.95 quantiles.