caa a22 4500 445818492 CHVBK 20180317145236.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s00792-011-0374-3 doi (NATIONALLICENCE)springer-10.1007/s00792-011-0374-3 The characterization of Thermotoga maritima ferritin reveals an unusual subunit dissociation behavior and efficient DNA protection from iron-mediated oxidative stress [Elektronische Daten] [Pierpaolo Ceci, Elena Forte, Gisa Di Cecca, Manuela Fornara, Emilia Chiancone] Ferritin from the hyperthermophilic anaerobe Thermotoga maritima, a bacterium of ancient phylogenetic origin, is structurally similar to known bacterial and eukaryotic ferritins: 24 identical subunits assemble into a shell having octahedral symmetry and a Mr of about 460kDa. T. maritima ferritin (TmFtn), purified to homogeneity as a recombinant protein, contains approximately 2-3 iron atoms and can incorporate efficiently up to 3,500 atoms in the form of a ferric oxy-hydroxide mineral at 80°C, the optimal growth temperature of the bacterium. The 24-mer unexpectedly dissociates reversibly into dimers at low ionic strengths. In turn, dimers re-associate into the native 24-mer assembly at high protein concentrations and upon incorporation of iron micelles containing at least 500 Fe(III). TmFtn uses O2 as efficient iron oxidant. The reaction stoichiometry is 3-4 O2:Fe(II) as in all bacterial ferritins. Accordingly no H2O2 is released into solution, a feature reflected in the in vitro ability of TmFtn to reduce significantly iron-mediated oxidative damage to DNA at 80°C. A similar TmFtn-mediated ROS detoxifying role likely occurs in the bacterium which lacks the SOD/catalase defense systems of the aerobic world. Springer, 2011 Thermotoga maritima ferritin nationallicence Subunit association-dissociation properties nationallicence Iron incorporation nationallicence DNA protection nationallicence ROS detoxification nationallicence Ceci Pierpaolo Institute of Molecular Biology & Pathology, CNR, Rome, Italy aut Forte Elena Department of Biochemical Sciences "A. Rossi Fanelli”, Sapienza, University of Rome, P.le A. Moro 5, 00185, Rome, Italy aut Di Cecca Gisa Department of Biochemical Sciences "A. Rossi Fanelli”, Sapienza, University of Rome, P.le A. Moro 5, 00185, Rome, Italy aut Fornara Manuela Department of Biochemical Sciences "A. Rossi Fanelli”, Sapienza, University of Rome, P.le A. Moro 5, 00185, Rome, Italy aut Chiancone Emilia Institute of Molecular Biology & Pathology, CNR, Rome, Italy aut Extremophiles Springer Japan 15/3(2011-05-01), 431-439 1431-0651 15:3<431 2011 15 792 https://doi.org/10.1007/s00792-011-0374-3 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00792-011-0374-3 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ceci Pierpaolo Institute of Molecular Biology & Pathology, CNR, Rome, Italy aut NATIONALLICENCE 700 1- Forte Elena Department of Biochemical Sciences "A. Rossi Fanelli”, Sapienza, University of Rome, P.le A. Moro 5, 00185, Rome, Italy aut NATIONALLICENCE 700 1- Di Cecca Gisa Department of Biochemical Sciences "A. Rossi Fanelli”, Sapienza, University of Rome, P.le A. Moro 5, 00185, Rome, Italy aut NATIONALLICENCE 700 1- Fornara Manuela Department of Biochemical Sciences "A. Rossi Fanelli”, Sapienza, University of Rome, P.le A. Moro 5, 00185, Rome, Italy aut NATIONALLICENCE 700 1- Chiancone Emilia Institute of Molecular Biology & Pathology, CNR, Rome, Italy aut NATIONALLICENCE 773 0- Extremophiles Springer Japan 15/3(2011-05-01), 431-439 1431-0651 15:3<431 2011 15 792 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer