A novel non-heme iron-binding ferritin related to the DNA-binding proteins of the Dps family in Listeria innocua.
A multimeric protein that behaves functionally as an authentic ferritin has been isolated from the Gram-positive bacterium Listeria innocua. The purified protein has a molecular mass of about 240,000 Da and is composed of a single type of subunit (18,000 Da). L. innocua ferritin is able to oxidize and sequester about 500 iron atoms inside the protein cage. The primary structure reveals a high similarity to the DNA-binding proteins designated Dps. Among the proven ferritins, the most similar sequences are those of mammalian L chains that appear to share with L. innocua ferritin the negatively charged amino acids corresponding to the iron nucleation site. In L. innocua ferritin, an additional aspartyl residue may provide a strong complexing capacity that renders the iron oxidation and incorporation processes extremely efficient. This study provides the first experimental evidence for the existence of a non-heme bacterial ferritin that is related to Dps proteins, a finding that lends support to the recent suggestion of a common evolutionary origin of these two protein families.
Bozzi
M
M
Centro Biologia Molecolare, Consiglio Nazionale delle Ricerche, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Università la Sapienza, 00185 Roma, Italy.
Mignogna
G
G
Stefanini
S
S
Barra
D
D
Longhi
C
C
Valenti
P
P
Chiancone
E
E
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D005293:Ferritins / Q000737:chemistry*; D008087:Listeria / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016415:Sequence Alignment
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C083911:DPS protein, Bacteria; D005293:Ferritins