Ceci 2011 Extremophiles: Difference between revisions

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Ceci P, Forte E, Di Cecca G, Fornara M, Chiancone E (2011) The characterization of Thermotoga maritima ferritin reveals an unusual subunit dissociation behavior and efficient DNA protection from iron-mediated oxidative stress. Extremophiles 15:431-9.

» PMID: 21487935

Ceci P, Forte E, Di Cecca G, Fornara M, Chiancone E (2011) Extremophiles

Abstract: 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 460 kDa. 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. • Keywords: Thermotoga maritima ferritin, Subunit association-dissociation properties, Iron incorporation, DNA protection, ROS detoxification

Labels:

Organism: Rat, Eubacteria

Preparation: Enzyme

HRR: Oxygraph-2k

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 {{Publication
-|title=Ceci P, Forte E, Di Cecca G, Fornara M, Chiancone E (2011) The characterization of Thermotoga maritima ferritin reveals an unusual subunit dissociation behavior and efficient DNA protection from iron-mediated oxidative stress. Extremophiles 15(3):431-439.
+|title=Ceci P, Forte E, Di Cecca G, Fornara M, Chiancone E (2011) The characterization of ''Thermotoga maritima'' ferritin reveals an unusual subunit dissociation behavior and efficient DNA protection from iron-mediated oxidative stress. Extremophiles 15:431-9.
-|info=[http://www.ncbi.nlm.nih.gov/pubmed/21487935 PMID:21487935]
+|info=[http://www.ncbi.nlm.nih.gov/pubmed/21487935 PMID: 21487935]
 |authors=Ceci P, Forte E, Di Cecca G, Fornara M, Chiancone E
 |year=2011
 |journal=Extremophiles
-|abstract=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 460 kDa. 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 O(2) as efficient iron oxidant. The reaction stoichiometry is 3-4 O(2):Fe(II) as in all bacterial ferritins. Accordingly no H(2)O(2) 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.
+|abstract=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 460 kDa. ''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 O<sub>2</sub> as efficient iron oxidant. The reaction stoichiometry is 3-4 O<sub>2</sub>:Fe(II) as in all bacterial ferritins. Accordingly no H<sub>2</sub>O<sub>2</sub> 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.
-|keywords=thermotoga maritima ferritin, subunit association-dissociation properties, iron incorporation, DNA protection, ros detoxification
+|keywords=Thermotoga maritima ferritin, Subunit association-dissociation properties, Iron incorporation, DNA protection, ROS detoxification
 }}
 {{Labeling
+|organism=Rat, Eubacteria
+|preparations=Enzyme
 |instruments=Oxygraph-2k
 }}