MOLECULAR CHARACTERIZATION OF AN OUTER-MEMBRANE PROTEIN OF ACTINOBACILLUS-ACTINOMYCETEMCOMITANS BELONGING TO THE OMPA FAMILY

The major outer membrane protein (OMP) of Actinobacillus actinomycetem comitans is an OmpA homolog that demonstrates electrophoretic heat mod ifiability. The gene encoding this protein,vas isolated from a genomic library of A. actinomycetemcomitans NCTC 9710 by immunoscreening with serum from a patient with localized juvenile periodontitis. Expressio n of the cloned gene in Escherichia coli and subsequent Western blot a nalysis revealed a protein,vith an approximate molecular mass of 34 kD a. The amino acid sequence predicted from the cloned gene demonstrated that the mature protein had a molecular mass of 34,911 Da and signifi cant identity to members of the OmpA family of proteins. We have named the major OMP of A. actinomycetemcomitans Omp34, and its correspondin g gene has been named omp34.