Saccharophagus degradans 2-40 is a Gram-negative, aerobic, motile gamma- Proteobacterium, which was isolated from decaying salt marsh cord grass Spartina alterniflora in the Chesapeake Bay watershed. It is a prominent member of newly discovered group of marine and estuarine bacteria that are capable of degrading at least 10 different complex polysaccharides. The focus of this research was elucidate the biological function of cadherin (CA) domains, cadherin-like (CADG) domains and TSP_3 modules that appear in large, surface proteins of S. degradans 2-40. We proposed and tested the notion that bacterial cadherin may also be involved in homophilic and heterophilic interactions. Thus, CA and CADG domains were examined for possible protein-protein interactions with other S. degradans 2-40 protein domains, including TSP_3 and CBM6. In addition, these domains were also tested for direct adhesion to bacterial cell surface. In summary, this research evaluated the biological roles of newly discovered adhesive modules in the S. degradans 2-40. The research showed that these prokaryotic modules can function in protein-protein interaction and in binding to complex carbohydrates.