Structure of Two Iron-binding Proteins from Bacillus anthracis

Abstract

Bacillus anthracis is currently under intense investigation due to its primary importance as a human pathogen. Particularly important is the development of novel anti-anthrax vaccines, devoid of the current side effects. A novel class of immunogenic bacterial proteins consists of dodecamers homologous to the DNA-binding protein of Escherichia coli (Dps). Two Dps homologous genes are present in the B. anthracis genome. The crystal structures of these two proteins (Dlp-1 and Dlp-2) have been determined and are presented here. They are sphere-like proteins with an internal cavity. We also show that they act as ferritins and are thus involved in iron uptake and regulation, a fundamental function during bacterial growth.

Iron-oxo clusters biomineralizing on protein surfaces: Structural analysis of Halobacterium salinarum DpsA in its low- and high-iron states

“…The iron is coordinated in a hexagonally distorted manner to two water molecules and the conserved residues Asp-79 (A), Glu-83 (A), His-52 (B) from two monomers, which are related by a twofold symmetry axis (data not shown). Such a geometry is similar to the FOCs found in the structures from L. innocua, B. anthracis, and E. coli (13)(14)(15). In the high-iron state dataset FE30, two additional subsites, F2 and F3, were detected at the FOC (Fig.…”

“…Hereby, the main entry of iron and other ionic species into these members of the Dps subfamily is postulated to occur along pores that penetrate the protein shell at the threefold axes of symmetry (9,13), and that were also identified as entrance sites in the 24-mer ferritins (2). In the crystal structures of Dps proteins from E. coli (14), L. innocua (13), and Bacillus anthracis (15), these access channels are conserved, besides an interfacial iron-binding site that was assigned in these Dps-like ferritins as a di-iron ferroxidase center for catalytic iron oxidation.…”

The multifunctional histone-like protein Lsr2 protects mycobacteria against reactive oxygen intermediates

“…These results suggest that Lsr2 does not efficiently remove hydroxyl radicals. Most proteins of the Dps family have been shown to specifically bind iron (12,13,14). Iron sequestration interferes with the Fenton reaction, reduces ROI generation, and thereby reduces potential DNA damage.…”

Structure and immunomodulatory property relationship in NapA of Borrelia burgdorferi

“…The NapA monomer ( Fig. 2A) was found to adopt the typical folding of the Dps-like family members [1,[17][18][19] characterized by a four-helix bundle. Helices A (residues from 15 to 40) and B (from 46 to 53) are connected through a long strand to helices C (residues from 113 to 127) and D (residues from 133 to 153).…”

“…Three-dimensional model of the NapA monomer and oligomer. (A) Superposition of Cα chain trace of monomer of NapA (yellow) to that of other proteins of the family: Dps from Bacillus brevis (blue, PDB code 1N1Q) [21], HP-NAP from Helicobacter pylori (green, PDB code 1JI4) [18], Dlp-2 from Bacillus anthracis (red, PDB code 1JIG) [17]. Residues are numbered according to [7].…”