Characterization of the Coxiella burnetii sucB gene encoding an immunogenic dihydrolipoamide succinyltransferase

The Coxiella burnetii sucB gene encoding the dihydrolipoamide succinyltrans ferase (E2o) enzyme was cloned by immunological screening of a lambda EMBL3 genomic library prepared from strain Nine Mile DNA and sequenced. The homo logy of the cloned gene product to the counterpart in Escherichia coli was 54.3 %, but the homology of the N-terminal region was only 42 %. The gene w as expressed in E. coli as an independent unit from its own promoter, produ cing an immunoreactive protein of about 50 kDa on SDS-PAGE which reacted wi th antisera from laboratory animals and sera from human patients with acute Q fever. The study results suggest that the C, burnetii E2o enzyme may ser ve as a potential target antigen for diagnostic assays for Q fever.