Properties of a copper-containing cytochrome ba3: a second terminal oxidase from the extreme thermophile Thermus thermophilus.

Zimmermann, Bárbara H.; Nitsche, Carmen I.; Fee, James A.; Rusnak, Frank; Münck, Eckard

doi:10.1073/pnas.85.16.5779

Cited by 135 publications

(153 citation statements)

References 23 publications

(15 reference statements)

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“…The results of a preparation from 500 g wet cells are shown in Table 1. Losses of heme a and heme c during the preparation are partially due to separation from an alternative ba3 oxidase [24] and different cytochromes c in this organism.…”

Section: Resultsmentioning

confidence: 94%

Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c₁aa₃’ of Thermus thermophilus

Buse

Hensel

Fee

1989

European Journal of Biochemistry

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The terminal cytochrome claa3 of the respiratory chain of Thermus thermophilus has been isolated and purified to homogeneity by a novel procedure. The two subunit proteins (55 and 33 kDa) have been characterized chemically. Computer searches with partial amino acid sequences obtained from both subunits show that the larger subunit belongs to the cytochrome oxidase subunit I protein family while the smaller covalently hemebinding subunit is not a cytochrome c1 but appears to be a fused protein between cytochrome c and cytochrome oxidase subunit 11.With respect to the 16-S rRNA-derived phylogeny of procaryotes, the results show that the genetic information for an 02-reacting cytochrome oxidase (EC 1.9.3.1) existed already in early eubacteria.Respiratory chains of many bacteria contain terminal 02-reducing oxidases with similar spectroscopic and functional properties but much simpler subunit structure than the mitochondrial cytochrome-c oxidase (EC 1.9.3.1) [I -31. Thus the enzyme from the plasma membrane of Paracoccus denitrificans can either be isolated as a functional (02-reducing and H+-pumping) two-or three-subunit complex homologous to the mtDNA-coded subunits I, I1 and eventually 111 of the mitochondrial enzyme [4, 51. From these data it had been inferred that subunits I and 11 represent a minimum catalytic structure capable of binding the canonical four metal centers (heme a, heme u3, CuA and CuB) and of catalysing the reaction 4Cytc" + O2 + (4 + n)H' = 4Cytc3+ + 2H2O + nH:where i and o refer to the inner and outer sites of the membrane. Furthermore, the sequence analyses with the Paracoccus enzyme have suggested that this bacterium is a descendant from those ancient bacteria from which eucaryotic mitochondria also originated under the selection pressure of a rising oxygen atmosphere [6]. The origin of more distantly related aerobic bacterial lines is, however, assumed to fall beyond the earths' O2 horizon and, consequently, it has been argued that O2 respiration evolved several times independently [7].Recently a terminal claa3 oxidase from the strictly aerobic bacterium Thermus thermophilus has been described [8, 91

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Section: Resultsmentioning

confidence: 94%

Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c₁aa₃’ of Thermus thermophilus

Buse

Hensel

Fee

1989

European Journal of Biochemistry

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“…The remaining part of the sequence (two-thirds of the protein), hosting the second heme-binding site, showed ϳ50% sequence identity (Fig. 1B) with the well-characterized cytochrome c 552 from T. thermophilus, the substrate of ba 3 and caa 3 cytochrome c oxidases (21,35,37), the two respiratory terminal oxidases of this organism (11,40).…”

Section: Resultsmentioning

confidence: 99%

A Sulfite Respiration Pathway from Thermus thermophilus and the Key Role of Newly Identified Cytochrome c ₅₅₀

et al. 2011

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Sulfite, produced for instance during amino acid metabolism, is a very reactive and toxic compound. Various detoxification mechanisms exist, but sulfite oxidoreductases (SORs) are one of the major actors in sulfite remediation in bacteria and animals. Here we describe the existence of an operon in the extreme thermophilic bacterium Thermus thermophilus HB8 encoding both a SOR and a diheme c-type cytochrome. The in vitro analysis clearly showed that the newly identified cytochrome c 550 acts as an acceptor of the electrons generated by the SOR enzyme during the oxidation of sulfite. The electrons are then rapidly shuttled via cytochrome c 552 to the terminal ba 3 -and caa 3 -type oxidases, thereby unveiling a novel electron transfer pathway, linking sulfite oxidation to oxygen reduction in T. thermophilus: sulfite 3 SOR HB8 3 cytochrome c 550 3 cytochrome c 552 3 ba 3 oxidase/caa 3 oxidase 3 O 2 . The description of the complete pathway reveals that electrons generated during sulfite oxidation by the SOR are funneled into the respiratory chain, participating in the energy production of T. thermophilus.

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“…The enzyme contains the four redox-active metal centers (8)(9)(10) and functions as a terminal oxidase for aerobic metabolism under limited oxygen concentration (8)(9)(10)(11). It also possesses NO reductase activity (12) suggesting shared evolutionary lineage of O 2 ∕NO reduction in this enzyme.…”

mentioning

confidence: 99%

CO impedes superfast O ₂ binding in ba ₃ cytochrome oxidase from Thermus thermophilus

Szundi

Funatogawa²,

Fee³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

100

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Kinetic studies of heme-copper terminal oxidases using the CO flow-flash method are potentially compromised by the fate of the photodissociated CO. In this time-resolved optical absorption study, we compared the kinetics of dioxygen reduction by ba 3 cytochrome c oxidase from Thermus thermophilus in the absence and presence of CO using a photolabile O 2 -carrier. A novel doublelaser excitation is introduced in which dioxygen is generated by photolyzing the O 2 -carrier with a 355 nm laser pulse and the fully reduced CO-bound ba 3 simultaneously with a second 532-nm laser pulse. A kinetic analysis reveals a sequential mechanism in which O 2 binding to heme a 3 at 90 μM O 2 occurs with lifetimes of 9.3 and 110 μs in the absence and presence of CO, respectively, followed by a faster cleavage of the dioxygen bond (4.8 μs), which generates the P intermediate with the concomitant oxidation of heme b. The second-order rate constant of 1 × 10 9 M −1 s −1 for O 2 binding to ba 3 in the absence of CO is 10 times greater than observed in the presence of CO as well as for the bovine heart enzyme. The O 2 bond cleavage in ba 3 of 4.8 μs is also approximately 10 times faster than in the bovine enzyme. These results suggest important structural differences between the accessibility of O 2 to the active site in ba 3 and the bovine enzyme, and they demonstrate that the photodissociated CO impedes access of dioxygen to the heme a 3 site in ba 3 , making the CO flow-flash method inapplicable.double-laser technique | T. thermophilus ba3 | oxygen reduction | slow-fast kinetics | O2 channel T he reduction of dioxygen to water in the heme-copper oxidases takes place at the high-spin heme a 3 and Cu B heterodinuclear center (for review, see refs. 1 and 2). The reaction has been extensively investigated in several aa 3 -oxidases by timeresolved spectroscopic techniques in combination with the CO flow-flash technique (1, 2), in which the reaction is initiated by photolyzing CO bound to heme a 3 2þ in the presence of O 2 (3). The O 2 reduction has commonly been interpreted in terms of a unidirectional sequential mechanism (Scheme 1).The O 2 reduction in Thermus thermophilus ba 3 , a B-type oxidase with distant sequence homology to the A-type oxidases (4), has received much less attention (5-7). The enzyme contains the four redox-active metal centers (8-10) and functions as a terminal oxidase for aerobic metabolism under limited oxygen concentration (8-11). It also possesses NO reductase activity (12) suggesting shared evolutionary lineage of O 2 ∕NO reduction in this enzyme. In ba 3 , the thermal dissociation of CO from heme a 3 2þ in the dark is significantly faster (0.8 s −1 ) (5) than in the bovine aa 3 (0.023 s −1 ) (3, 13), and therefore CO flow-flash experiments on ba 3 require fast mixing; such experiments have recently been reported (6, 7). Moreover, the Cu B þ -CO complex formed following CO photolysis from heme a 3 2þ in ba 3 decays with a lifetime of approximately 30 ms (14), a rate much slower than that of O 2 binding to heme ...

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Properties of a copper-containing cytochrome ba3: a second terminal oxidase from the extreme thermophile Thermus thermophilus.

Cited by 135 publications

References 23 publications

Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c₁aa₃’ of Thermus thermophilus

Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c₁aa₃’ of Thermus thermophilus

A Sulfite Respiration Pathway from Thermus thermophilus and the Key Role of Newly Identified Cytochrome c ₅₅₀

CO impedes superfast O ₂ binding in ba ₃ cytochrome oxidase from Thermus thermophilus

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Properties of a copper-containing cytochrome ba3: a second terminal oxidase from the extreme thermophile Thermus thermophilus.

Cited by 135 publications

References 23 publications

Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c1aa3’ of Thermus thermophilus

Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c1aa3’ of Thermus thermophilus

A Sulfite Respiration Pathway from Thermus thermophilus and the Key Role of Newly Identified Cytochrome c 550

CO impedes superfast O 2 binding in ba 3 cytochrome oxidase from Thermus thermophilus

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Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c₁aa₃’ of Thermus thermophilus

Evidence for cytochrome oxidase subunit I and a cytochrome c– subunit II fused protein in the cytochrome ‘c₁aa₃’ of Thermus thermophilus

A Sulfite Respiration Pathway from Thermus thermophilus and the Key Role of Newly Identified Cytochrome c ₅₅₀

CO impedes superfast O ₂ binding in ba ₃ cytochrome oxidase from Thermus thermophilus