A cryptic DNA sequence, isolated from Actinobacillus pleuropneumoniae, confers a hemolytic activity upon Escherichia...

A hemolytic recombinant clone on Escherichia coli was obtained from a genomic library of Actinobacillus pleuropneumoniae. The clone possessed a recombinant plasmid, pHLY1, carrying an insert DNA of 1 kilobases. A 21 kilodaltons protein, which is assumed to be a fusion protein with a tetracycline resistant protein of pBR322, was encoded by pHLY1. The nucleotide sequence and its deduced amino acid sequence were different from those of the previously reported hemolysin genes of A. pleuropneumoniae. Furthermore, the amino acid sequence did not show a significant homology with other published sequences in the SWISS-PROT Protein Sequence Data Bank.