Geometric invariant core for the C-L and C-H1 domains of immunoglobulin molecules

A previously developed algorithmic method for identifying a geometric invar iant of protein structures, termed geometrical core, is extended to the C-L and C-H1 domains of immunoglobulin molecules. The method uses the matrix o f C-alpha - C-alpha distances and does not require the usual superposition of structures. The result of applying the algorithm to 53 Immunoglobulin st ructures led to the identification of two geometrical core sets of C-alpha, atom positions for the C-L and C-H1 domains,