The Role of Heme Binding by DNA-protective Protein from Starved Cells (Dps) in the Tolerance of Porphyromonas gingivalis to Heme Toxicity

Abstract

Background: Iron-storage Dps proteins are expressed in prokaryotes to confer resistance to specific stressful conditions. Results: Dps from Porphyromonas gingivalis (PgDps) is able to bind heme through a conserved cysteine and protects DNA against H 2 O 2 -mediated degradation. Conclusion:The heme sequestration property of PgDps confers resistance to heme toxicity. Significance: This Dps protection strategy may be common among members of the order Bacteroidales.

Ferritin-like family proteins in the anaerobe Bacteroides fragilis: when an oxygen storm is coming, take your iron to the shelter

“…The Dps proteins found in B. cellulosilyticus , B. eggerthii , B. intestinalis , B. stercoris , B. uniformis , P. merdae , and P. distasonis contain two conserved cysteine residues (Cys100 and Cys160). Interestingly, Porphyromonas gingivalis Dps contains a single cysteine residue (Cys101, the corresponding residue of Bacteroides Dps Cys100) that coordinates a novel hemeiron binding property at the surface of the dodecameric protein (Gao et al 2012). Phylogenetically, the Bacteroides Dps is separated from the FtnA and DpsL branch.…”

The interplay between iron, haem and manganese in Porphyromonas gingivalis

“…This is also a novel way to store reactive iron outside the cell where it cannot cause damage to intracellular components. P. gingivalis has developed various intracellular oxidative stress defence systems, including superoxide dismutase (SOD) which can utilise either iron or manganese as co-factor, [107], the DNAbinding protein from starved cells (Dps) [108,109], alkyl hydroperoxide peroxidase subunit C (AhpC) [110] and rubrerythrin (Rbr) [111]. Superoxide dismutase (SOD) is the only known P. gingivalis oxidative defence system which requires manganese as a cofactor, however, the intracellular accumulation of manganese itself has been shown to have anti-oxidative properties, protecting P. gingivalis from atmospheric oxygen and hydrogen peroxide [102].…”

Binding Analysis of Ferritin with Heme Using α-Casein and Biotinylated-Hemin: Detection of Heme-Binding Capacity of Dpr Derived from Heme Synthesis-Deficient <i>Streptococcus mutans</i>

“…Although the amino acid homology between S. mutans Dpr and P. gingivalis Dps or horse L subunit is low (<20%) [1,4,24,25], these iron-binding proteins may have developed as a divergent heme-binding family. Although heme binding is likely to be common in iron-binding proteins forming nanocages, this heme binding may affect cellular redox homeostasis and heme metabolism by a unique heme-binding mechanism.…”

“…Bacterial DNA-binding protein from starved cells (Dps) is a decameric iron-binding protein that belongs to the ferritin superfamily, and its iron-binding capacity protects DNA from oxidative stress [11,12]. Recently, the heme binding of Dps from Porphyromonas gingivalis was demonstrated to protect DNA from heme-mediated oxidative stress, although the iron-binding protein has no DNA-binding capacity [4]. Dps possesses separate iron-and heme-binding sites, and sequestration of either iron or heme leads to protection from oxidative damage [4].…”

“…Recently, the heme binding of Dps from Porphyromonas gingivalis was demonstrated to protect DNA from heme-mediated oxidative stress, although the iron-binding protein has no DNA-binding capacity [4]. Dps possesses separate iron-and heme-binding sites, and sequestration of either iron or heme leads to protection from oxidative damage [4]. Additionally, the dpr (Dps-like peroxide resistance) gene product, Dpr, from heme-deficient Streptococcus mutans is unable to bind DNA, but its iron-binding limits the iron-catalyzed Fenton reaction [24,25]; however, its heme-binding has not been revealed yet.…”