Bozzi M, Mignogna G, Stefanini S, Barra D, Longhi C, Valenti P, Chiancone E
Centro Biologia Molecolare, Consiglio Nazionale delle Ricerche, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Università la Sapienza, 00185 Roma, Italy.
J Biol Chem. 1997 Feb 7;272(6):3259-65. doi: 10.1074/jbc.272.6.3259.
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.
一种在功能上表现为真正铁蛋白的多聚体蛋白已从革兰氏阳性细菌无害李斯特菌中分离出来。纯化后的蛋白分子量约为240,000道尔顿，由单一类型的亚基（18,000道尔顿）组成。无害李斯特菌铁蛋白能够在蛋白笼内氧化并螯合约500个铁原子。一级结构显示与指定为Dps的DNA结合蛋白高度相似。在已证实的铁蛋白中，最相似的序列是哺乳动物L链的序列，这些序列似乎与无害李斯特菌铁蛋白共享对应于铁成核位点的带负电荷氨基酸。在无害李斯特菌铁蛋白中，一个额外的天冬氨酰残基可能提供强大的络合能力，使铁的氧化和掺入过程极其高效。这项研究为存在与Dps蛋白相关的非血红素细菌铁蛋白提供了首个实验证据，这一发现支持了这两个蛋白家族最近关于共同进化起源的观点。
