Bacterioferritin B (BfrB) and Ferredoxin (Bfd) associate to regulate iron release in the pathogenic bacteria Pseudomonas aeruginosa (LB107)

Abstract

Iron is an essential cofactor in respiration, nitrogen fixation, photosynthesis, and DNA synthesis and repair. Iron is necessary for the survival of pathogens in the host, thus iron storage proteins may be potential targets for antibiotics. Bacterioferritin (BfrB) is a 440 kDa iron‐storage protein that forms a 24‐mer assembly made up of 12 dimers and adopts a spherical structure with a hollow interior cavity. The individual subunits adopt a structure that consists of 4 α‐helicies and a short C‐ terminal helix. Each BfrB dimer binds a heme molecule for a total of 12 hemes in the assembly. During the storage process, reactive Fe2+ is oxidized to Fe3+ and the BfrB 24‐mer functions to catalyze the conversion of Fe2+ to Fe3+, which is stored in the central core of the assembly. Then to release iron, a total of 12 ferredoxin (Bfd) molecules bind to the dimers on the surface of BfrB, one Bfd molecule per BfrB dimer, to facilitate the release when needed by the cells. Fe3+ is reduced to soluble Fe2+ by the transfer of electrons from Bfd through the heme molecules of BfrB into the interior cavity. Understanding the interactions that enable iron homeostasis in bacteria is important, as iron storage proteins could be potential targets for the development of antibiotics. The Olathe North SMART Team (Students Modeling A Research Topic) researched and modeled BfrB‐Bfd using 3D printing technology.Grant Funding Source: Supported by grants from NIH‐CTSA and NIH‐SEPA.