Abstract: A breast carcinoma tyrosine phosphoprotein, DDR (Discoidin Domain Receptor), that defines a novel class of receptor tyrosine kinases is presented. The DDR cDNA predicts a polypeptide C-terminal tyrosine kinase domain and an N-terminal domain similar to the Dictyostelium discoideum lectin discoidin I. These domains are connected by an extraordinary hydrophilic proline/glycine-rich domain, which is interrupted by a predicted transmembrane sequence. This extended proline/glycine-rich region suggests an unusual geometry of interaction with ligand or substrates. Discoidin I-type domains may interact with specific cell surface molecules.

Abstract: A breast carcinoma tyrosine phosphoprotein, DDR (Discoidin Domain Receptor), that defines a novel class of receptor tyrosine kinases is presented. The DDR cDNA predicts a polypeptide C-terminal tyrosine kinase domain and an N-terminal domain similar to the Dictyostelium discoideum lectin discoidin I. These domains are connected by an extraordinary hydrophilic proline/glycine-rich domain, which is interrupted by a predicted transmembrane sequence. This extended proline/glycine-rich region suggests an unusual geometry of interaction with ligand or substrates. Discoidin I-type domains may interact with specific cell surface molecules.

Abstract: A DNA expression vector is described which is derived from the highly efficient trp operon. The expression vector provides for the direct expression of an inserted gene or cDNA. Using the expression vector described herein, it is possible to obtain the protein coded by the gene or cDNA directly and not as a fusion protein. The expression vector comprises the promoter, operator and leader ribosomal binding site of the trp operon.

Abstract: A DNA expression vector which contains the trp promotor is described. The expression vector provides for the overproduction of .beta.-lactamase. Insertion of a gene or cDNA into the .beta.-lactamase gene of the expression vector results in the over-production of a fusion protein comprising a part of the .beta.-lactamase as the N-terminal end and the protein coded for by the inserted DNA as the C-terminal end. Using the expression vector described herein, it is possible to obtain large amounts of the fusion protein. A fusion protein containing the surface antigen of Hepatitis B virus and a vaccine containing this fusion protein are also described.