Production of a Renibacterium salmoninarum hemolysin fusion protein in Escherichia coli K12

Gene rsh encoding a novel hemolysin of Renibacterium salmoninarum was fused to the lacZ gene of the pAX5+ plasmid vector to facilitate production of a 160 kDa beta -galactosidase fusion protein. The soluble fusion protein was produced cytoplasmically in Escherichia coli XL1-Blue and purified using affinity chromatography. The fusion protein retained epitopes which were identified in components present in in vitro cultures of R. salmoninarum . Western blots of R. salmoninarum cell extracts which were probed with an antiserum raised against the affinity purified fusion protein predominantly recognized bands of apparent molecular weights 82 and 78 kDa as well as a number of other bands which may represent breakdown products of the native protein. No components were detected in extracellular products and iron-restricted culture conditions did not obviously affect the production of these components.