Figure 4

Definitions and illustration of coverage rates. We considered a set of seven words of four structural letters (SPBD, UQRS, RBTU, DOCI, ZPCD, PCDU, DUGO), grouping 14 seven-residue fragments. Let us consider that these words and their occurrence are examples and not the real occurrences in the data set. From this set of words, we focused on three words, named restricted set and presented in red in A, grouping seven seven-residue fragments. Various coverage rates were calculated for these words. A: word coverage, the fraction of structural words included in the restricted set. B: fragment coverage, the fraction of fragments encoded by words from the restricted set. C: loop-length coverage, the fraction of residues in loops covered by words from the restricted set. D: protein coverage, the fraction of proteins containing at least one of the words from the restricted set.