A tyrosine residue deprotonates during oxygen reduction by the <i>caa</i>3 reductase from <i>Rhodothermus marinus</i>

Pereira, Manuela M.; Sousa, Filipa L.; Teixeira, Miguel; Nyquist, Rebecca M.; Heberle, Joachim

doi:10.1016/j.febslet.2006.01.055

Cited by 20 publications

(18 citation statements)

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“…Besides an NADH: quinone oxidoreductase (Fernandes et al, 2002Melo et al, 2005) and a succinate:quinone oxidoreductase (Fernandes et al, 2001), it contains a quinol:cytochrome oxidoreductase different from the bc 1 complex (Pereira et al, 1999a) and two oxygen reductases: a cbb 3 (Pereira et al, 2000a) and a caa 3 (Pereira et al, 1999b(Pereira et al, , 2000b(Pereira et al, , 2006Santana et al, 2001;Soares et al, 2004), members of type C and A2 family of haem copper oxygen reductases, respectively. Besides an NADH: quinone oxidoreductase (Fernandes et al, 2002Melo et al, 2005) and a succinate:quinone oxidoreductase (Fernandes et al, 2001), it contains a quinol:cytochrome oxidoreductase different from the bc 1 complex (Pereira et al, 1999a) and two oxygen reductases: a cbb 3 (Pereira et al, 2000a) and a caa 3 (Pereira et al, 1999b(Pereira et al, , 2000b(Pereira et al, , 2006Santana et al, 2001;Soares et al, 2004), members of type C and A2 family of haem copper oxygen reductases, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…The R. marinus respiratory chain has been extensively characterized. Besides an NADH: quinone oxidoreductase (Fernandes et al, 2002Melo et al, 2005) and a succinate:quinone oxidoreductase (Fernandes et al, 2001), it contains a quinol:cytochrome oxidoreductase different from the bc 1 complex (Pereira et al, 1999a) and two oxygen reductases: a cbb 3 (Pereira et al, 2000a) and a caa 3 (Pereira et al, 1999b(Pereira et al, , 2000b(Pereira et al, , 2006Santana et al, 2001;Soares et al, 2004), members of type C and A2 family of haem copper oxygen reductases, respectively. In this study the purification and characterization of a third oxygen reductase from R. marinus are described.…”

Section: Introductionmentioning

confidence: 99%

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Aba₃oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus

Verissimo

Pereira

Melo

et al. 2007

FEMS Microbiology Letters

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The aerobic respiratory chain of the thermohalophilic bacterium Rhodothermus marinus has been extensively studied. In this study the isolation and characterization of a third oxygen reductase expressed in this organism are described. This newly isolated enzyme is a typical member of the type B family of haem-copper oxygen reductases, showing 43% amino acid sequence identity and 63% similarity with the ba3 oxygen reductase from Thermus thermophilus. It constitutes two subunits with apparent molecular masses of 42 and 38 kDa. It contains a low-spin B-type haem and a high-spin A-type haem. A stoichiometry of 1B: 1A haem per protein was obtained by spectral integration of UV-visible spectra. Metal analysis showed the presence of two iron and three copper ions, which is in agreement with the existence of a CuA centre. Taking advantage of having two spectroscopically distinct haems, the redox behaviour of the ba3 oxygen reductase was analysed and discussed in the framework of a model with interacting centres. Both haems, B and A, present two transitions, have unusually low reduction potentials of -65 mV and an interaction potential of -52.5 mV.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Aba₃oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus

Verissimo

Pereira

Melo

et al. 2007

FEMS Microbiology Letters

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“…marinus , the tyrosine of the YS gate has been reported to deprotonate during the gating event as evidenced by FTIR difference spectroscopy 20 . This observation is counter to earlier pK a calculations, which indicate that the tyrosine remains protonated 21 .…”

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confidence: 99%

Structural insights into electron transfer in caa3-type cytochrome oxidase

Lyons

Aragão

Slattery

et al. 2012

Nature

116

143

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Summary Paragraph Cytochrome c oxidase is a member of the heme copper oxidase superfamily (HCO)1. HCOs function as the terminal enzymes in the respiratory chain of mitochondria and aerobic prokaryotes, coupling molecular oxygen reduction to transmembrane proton pumping. Integral to the enzyme’s function is the transfer of electrons from cytochrome c to the oxidase via a transient association of the two proteins. Electron entry and exit are proposed to occur from the same site on cytochrome c2–4. Here we report the crystal structure of the caa3-type cytochrome oxidase from Thermus thermophilus, which has a covalently tethered cytochrome c domain. Crystals were grown in a bicontinuous mesophase using a synthetic short-chain monoacylglycerol as the hosting lipid. From the electron density map, at 2.36 Å resolution, a novel integral membrane subunit and a native glycoglycerophospholipid embedded in the complex were identified. Contrary to previous electron transfer mechanisms observed for soluble cytochrome c, the structure reveals the architecture of the electron transfer complex for the fused cupredoxin/cytochrome c domain which implicates different sites on cytochrome c for electron entry and exit. Support for an alternative to the classical proton gate characteristic of this HCO class is presented.

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“…In the A 2 family, the position of the carboxyl group of Glu242 is occupied by an OH group of tyrosine residue located on the adjacent helix turn. Reversible deprotonation of the tyrosine has been confirmed by IR analysis [80]. CcOs belonging to the B and C families do not have an active D-pathway.…”

Section: Diversity In Proton Transfer Pathwaysmentioning

confidence: 78%

“…These results reveal significant variances of the structures of the proton transfer pathways [79,80]. The CcOs discovered thus far have been classified into 4 families, A 1 , A 2 , B, and C [79].…”

Section: Diversity In Proton Transfer Pathwaysmentioning

confidence: 89%

Respiratory Conservation of Energy with Dioxygen: Cytochrome c Oxidase

Shimada¹,

Shinzawa‐Itoh²

2014

Sustaining Life on Planet Earth: Metalloenzymes Mastering Dioxygen and Other Chewy Gases

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Cytochrome c oxidase (CcO) is the terminal oxidase of cell respiration which reduces molecular oxygen (O₂) to H2O coupled with the proton pump. For elucidation of the mechanism of CcO, the three-dimensional location and chemical reactivity of each atom composing the functional sites have been extensively studied by various techniques, such as crystallography, vibrational and time-resolved electronic spectroscopy, since the X-ray structures (2.8 Å resolution) of bovine and bacterial CcO have been published in 1995.X-ray structures of bovine CcO in different oxidation and ligand binding states showed that the O₂reduction site, which is composed of Fe (heme a 3) and Cu (CuB), drives a non-sequential four-electron transfer for reduction of O₂to water without releasing any reactive oxygen species. These data provide the crucial structural basis to solve a long-standing problem, the mechanism of the O₂reduction.Time-resolved resonance Raman and charge translocation analyses revealed the mechanism for coupling between O₂reduction and the proton pump: O₂is received by the O₂reduction site where both metals are in the reduced state (R-intermediate), giving the O₂-bound form (A-intermediate). This is spontaneously converted to the P-intermediate, with the bound O₂fully reduced to 2 O²⁻. Hereafter the P-intermediate receives four electron equivalents from the second Fe site (heme a), one at a time, to form the three intermediates, F, O, and E to regenerate the R-intermediate. Each electron transfer step from heme a to the O₂reduction site is coupled with the proton pump.X-ray structural and mutational analyses of bovine CcO show three possible proton transfer pathways which can transfer pump protons (H) and chemical (water-forming) protons (K and D). The structure of the H-pathway of bovine CcO indicates that the driving force of the proton pump is the electrostatic repulsion between the protons on the H-pathway and positive charges of heme a, created upon oxidation to donate electrons to the O₂reduction site. On the other hand, mutational and time-resolved electrometric findings for the bacterial CcO strongly suggest that the D-pathway transfers both pump and chemical protons. However, the structure for the proton-gating system in the D-pathway has not been experimentally identified. The structural and functional diversities in CcO from various species suggest a basic proton pumping mechanism in which heme a pumps protons while heme a 3 reduces O₂as proposed in 1978.

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A tyrosine residue deprotonates during oxygen reduction by the caa3 reductase from Rhodothermus marinus

Cited by 20 publications

References 20 publications

Aba₃oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus

Aba₃oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus

Structural insights into electron transfer in caa3-type cytochrome oxidase

Respiratory Conservation of Energy with Dioxygen: Cytochrome c Oxidase

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A tyrosine residue deprotonates during oxygen reduction by the caa3 reductase from Rhodothermus marinus

Cited by 20 publications

References 20 publications

Aba3oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus

Aba3oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus

Structural insights into electron transfer in caa3-type cytochrome oxidase

Respiratory Conservation of Energy with Dioxygen: Cytochrome c Oxidase

Contact Info

Product

Resources

About

Aba₃oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus

Aba₃oxygen reductase from the thermohalophilic bacteriumRhodothermus marinus