Desulfovibrio vulgaris bacterioferritin uses H(2)O(2) as a co-substrate for iron oxidation and reveals DPS-like DNA protection and binding activities.
A gene encoding Bfr (bacterioferritin) was identified and isolated from the genome of Desulfovibrio vulgaris cells, and overexpressed in Escherichia coli. In vitro, H(2)O(2) oxidizes Fe(2+) ions at much higher reaction rates than O(2). The H(2)O(2) oxidation of two Fe(2+) ions was proven by Mössbauer spectroscopy of rapid freeze-quenched samples. On the basis of the Mössbauer parameters of the intermediate species we propose that D. vulgaris Bfr follows a mineralization mechanism similar to the one reported for vertebrate H-type ferritins subunits, in which a diferrous centre at the ferroxidase site is oxidized to diferric intermediate species, that are subsequently translocated into the inner nanocavity. D. vulgaris recombinant Bfr oxidizes and stores up to 600 iron atoms per protein. This Bfr is able to bind DNA and protect it against hydroxyl radical and DNase deleterious effects. The use of H(2)O(2) as an oxidant, combined with the DNA binding and protection activities, seems to indicate a DPS (DNA-binding protein from starved cells)-like role for D. vulgaris Bfr.
Requimte/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Caparica, Portugal.
Cristina G
CG
Timóteo
Márcia
M
Guilherme
Daniela
D
Penas
Filipe
F
Folgosa
Pedro
P
Tavares
Alice S
AS
Pereira
D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003573:Cytochrome b Group / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D016969:Desulfovibrio vulgaris / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005293:Ferritins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007501:Iron / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D013056:Spectrophotometry, Ultraviolet; D015204:Spectroscopy, Mossbauer
D001426:Bacterial Proteins; D003573:Cytochrome b Group; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; C083911:DPS protein, Bacteria; D005293:Ferritins; C018032:bacterioferritin; D006861:Hydrogen Peroxide; D007501:Iron