Nat Struct Biol. 1999 May;6(5):486-93.
Structure and interactions of NCAM modules 1 and 2, basic elements in neural cell adhesion.
Jensen PH, Soroka V, Thomsen NK,, Ralets I, Berezin V, Bock E, Poulsen FM.
Department of hemistry, Carlsberg Laboratory, Valby, Denmark.
Abstract
The structure in solution of the second Ig-module fragment of residues 117-208 of NCAM has been determined. Like the first Ig-module of residues 20-116, it belongs to the I set of the immunogloblin superfamily. Module 1 and module 2 interact weakly, and the binding sites of this interaction have been identified. The two-module fragment NCAM(20-208) is a stable dimer. Removal of the charged residues in these sites in NCAM(20-208) abolishes the dimerization. Modeling the dimer of NCAM(20-208) to fit the interactions of these charges produces one coherent binding site for the formation of two antiparallel strands of the first two NCAM modules. This mode of binding could be a major element in trans-cellular interactions in neural cell adhesion.