Cloning and expression of Bartonella henselae sucB gene encoding an immunogenic dihydrolipoamide succinyltransferase homologous protein

Immunoscreening of a ZAP genomic library of Bartonella henselae strain Houston-1 expressed in Escherichia coli resulted in the isolation of a clone containing 3.5 kb BamHI genomic DNA fragment. This 3.5 kb DNA fragment was found to contain a sequence of a gene encoding a protein with significant homology to the dihydrolipoamide succinyltransferase of Brucella melitensis (sucB). Subsequent cloning and DNA sequence analysis revealed that the deduced amino acid sequence from the cloned gene showed 66.5% identity to SucB protein of B. melitensis, and 43.4 and 47.2% identities to those of Coxiella burnetii and E. coli, respectively. The gene was expressed as a His-Nus A-tagged fusion protein. The recombinant SucB protein (rSucB) was shown to be an immunoreactive protein of about 115 kDa by Western blot analysis with sera from B. henselae-immunized mice. Therefore the rSucB may be a candidate antigen for a specific serological diagnosis of B. henselae infection.