Cloning of a Bacteroides gingivalis outer membrane protein gene in Escherichia coli

Gene banks of chromosomal DNA from Bacteroides gingivalis 381 were constructed using the bacteriophage replacement vector lambda L47.1. A clone encoding an outer membrane protein from B. gingivalis was identified by Western blot screening with antiserum raised against the outer membrane fraction of B. gingivalis 381 cells. The DNA insert contained within this phage was cloned into the plasmid vector pACYC184 to create the recombinant plasmid pMD123. An Escherichia coli transformant, MD123, containing pMD123 produced a protein having an apparent molecular weight of 40 kDa. The recombinant protein was purified, and amino acid analysis revealed the recombinant protein to have a relatively high content of hydrophobic amino acids (43.6%). Antiserum against the purified recombinant 40 kDa protein reacted with a polypeptide of similar size in the outer membrane fraction and vesicles of B. gingivalis.