HOMOGENEOUS AGGREGATION OF THE 14-KDA BETA-GALACTOSIDE-SPECIFIC VERTEBRATE LECTIN COMPLEX WITH ASIALOFETUIN IN MIXED SYSTEMS

The galactose-specific 14-kDa family of animals lectins are an evoluti onary conserved group of proteins that have been implicated in a wide variety of biological processes including cell proliferation, adhesion , and transformation. The present study demonstrates that the dimeric 14-kDa calf spleen lectin forms homogeneous aggregated cross-linked co mplexes with asialofetuin, a glycoprotein with multiple carbohydrate c hains possessing terminal galactose residues, in the presence of other lectins with similar specificities and cross-linking activities. Seve ral galactose-specific plant lectins also form homogeneous aggregated cross-linked complexes with ASF. These results demonstrate a new sourc e of specificity for the 14-kDa family of vertebrate lectins, namely, the ability to selectively cross-link and aggregate glycoproteins in m ixed systems. The results have important biological implications for t he interactions of multivalent lectins and glycoconjugates, as well as the thermodynamic interactions of multivalent molecules in general.