CLONING, SEQUENCING, AND CHARACTERIZATION OF THE GENE ENCODING FRPB, A MAJOR IRON-REGULATED, OUTER-MEMBRANE PROTEIN OF NEISSERIA-GONORRHOEAE

FrpB (for Fe-regulated protein B) is a 76-kDa outer membrane protein t hat is part of the iron regulon of Neisseria gonorrhoeae and Neisseria meningitidis. The frpB gene from gonococcal strain FA19 was cloned an d sequenced. FrpB was homologous to several TonB-dependent outer membr ane receptors of Escherichia coli as well as HemR of Yersinia enteroco litica and CopB of Moraxella catarrhalis. An Omega insertion into the frpB coding sequence caused a 60% reduction in Fe-55 uptake from heme, but careful analysis suggested that this effect was nonspecific. Whil e FrpB was related to the family of TonB-dependent proteins, a functio n in iron uptake could not be documented.