CATH is a novel
hierarchical classification of protein domain structures, which clusters
proteins at four major levels, Class(C),
Architecture(A), Topology(T)
and Homologous superfamily (H).
Class, derived from secondary
structure content, is assigned for more than 90% of protein structures
automatically. Architecture, which describes the gross orientation of secondary
structures, independent of connectivities, is currently assigned manually.
The topology level clusters structures according to their toplogical connections
and numbers of secondary structures. The homologous superfamilies cluster
proteins with highly similar structures and functions. The assignments
of structures to toplogy families and homologous superfamilies are made
by sequence and structure comparisons.
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