Abstract: The invention relates to bis-protein-DNA conjugates. A protein having an antigen specific binding activity is covalently linked to each end of a derivatized DNA molecule. The bis-protein-DNA conjugates can be used for immunoassays and measuring distances between proteins at up to 3.4 .ANG. resolution. The invention also relates to methods of synthesizing these bis-protein-DNA conjugates. Synthesis of the conjugates entails derivatizing the 5' or 3' end of a DNA oligonucleotide and covalently linking that DNA to a protein. The DNA can be indirectly conjugated to an antibody or Fab' fragment, using a avidin/streptavidin-biotin linkage. The conjugates of the invention can be used in immunoassays and PCR assays.

Abstract: A cloned gene (epr) encoding a novel extracellular protease, Epr, from Bacillus subtilis is described. Also described is a triple extracellular neutral, alkaline and serine protease deficient Bacillus subtilis mutant strain having deletions in the (npr), (apr) and (epr) genes encoding these proteases. The triple mutant strain was constructed by the gene conversion technique and produces about 1% of the extracellular proteolytic activity of the wild type. It is a particularly useful host for the production of heterologous proteins that are secreted into the growth medium.