Structures. (A) Histogram showing the distribution of PDB chains associated with individual families in Magnum. (B) Scatter plot of alignment length versus the number of PDB chains for each family. Glutamate synthase has the longest alignment length; lysozyme c and T4 phage lysozyme have the largest number of non-redundant PDB chains. (C) Frequency histograms for the proportions of alignment sites without structural information due to indels (gray), and unresolved areas of the structure (black). (D) Average PDB chain length plotted against the number of sites aligned to at least one PDB chain residue for families with at least two PDB chains (the coefficient of determination calculated by linear regression is also shown).