Geometric invariant core for the CL and CH1 domains of immunoglobulin molecules.

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