Binding of heme by Gardnerella vaginalis

It has been previously demonstrated that Gardnerella vaginalis could acquire iron from a number of different iron-containing compounds, including heme. In this study, the direct binding of heme by G. vaginalis strains was demonstrated utilizing a liquid broth heme-binding assay. Competition studies demonstrated that pretreatment of G. vaginalis cells with other iron sources such as hemoglobin, catalase, and lactoferrin did not affect heme binding. Also, heme binding was not inhibited by preincubation of G. vaginalis cells with protoporphyrin IX. Two potential heme-binding proteins with estimated molecular weights of 30 and 70 kDa were isolated using heme-agarose batch affinity chromatography.