Removing un-compact structures

Two filters exploit the radius of gyration, , to remove non-compact maps. Analysis of the high quality domains shows that , where is the length of the structure in residues. For each map, a coarse is first calculated by considering the centroids of secondary structures, and their C-terminal loops as point masses. A fine is also calculated by considering all matched residues (plus C-terminal loops) as point masses. Maps are removed if either value is greater than the maximum for compact domains of the same length.