Browsing by Subject "oxidoreductase"

Article

Detection of the His-heme Fe2+-NO species in the reduction of NO to N2O by ba3-oxidase from thermus thermophilus

Pinakoulaki, Eftychia; Ohta, T.; Soulimane, T.; Kitagawa, T.; Varotsis, Constantinos (2005)

Reaction pathways in the enzymatic formation and cleavage of the N-N and N-O bonds, respectively, are difficult to verify without the structure of the intermediates, but we now have such information on the heme a3 2+-NO ...

Article

Fourier transform infrared (FTIR) and step-scan time-resolved FTIR spectroscopies reveal a unique active site in cytochrome caa3 oxidase from Thermus thermophilus

Pinakoulaki, Eftychia; Soulimane, T.; Varotsis, Constantinos (2002)

Fourier transform infrared (FTIR) and step-scan time-resolved FTIR difference spectra are reported for the [carbonmonoxy]cytochrome caa3 from Thermus thermophilus. A major C-O mode of heme a3 at 1958 cm-1 and two minor ...

Article

Nitric oxide activation and reduction by heme-copper oxidoreductases and nitric oxide reductase

Pinakoulaki, Eftychia; Varotsis, Constantinos (2008)

The understanding of the dynamics and conformational control involved in the interplay between structure and function of nitric oxide reductase (Nor) and heme-copper oxidoreductases in their function to convert nitric oxide ...

Article

Observation of the equilibrium CuB-CO complex and functional implications of the transient heme a3 propionates in cytochrome ba3-CO from Thermus thermophilus. Fourier transform infrared (FTIR) and time-resolved step-scan FTIR studies

Koutsoupakis, Constantinos; Stavrakis, Stavros; Pinakoulaki, Eftychia; Soulimane, T.; Varotsis, Constantinos (2002)

We report the first evidence for the existence of the equilibrium CuB 1+-CO species of CO-bound reduced cytochrome ba3 from Thermus thermophilus at room temperature. The frequency of the C-O stretching mode of CuB 1+-CO ...

Article

The origin of the Fe IV = O intermediates in cytochrome aa 3 oxidase

Pinakoulaki, Eftychia; Daskalakis, Vangelis; Varotsis, Constantinos (2012)

The dioxygen reduction mechanism in cytochrome oxidases relies on proton control of the electron transfer events that drive the process. Proton delivery and proton channels in the protein that are relevant to substrate ...

Article

Probing the nitrite and nitric oxide reductase activity of cbb3 oxidase: Resonance Raman detection of a six-coordinate ferrous heme-nitrosyl species in the binuclear b3/CuB center

Loullis, Andreas; Pinakoulaki, Eftychia (2015)

In this work we report the first spectroscopic evidence demonstrating that cbb3 oxidase catalyzes the reduction of nitrite to nitrous oxide under reducing anaerobic conditions. The reaction proceeds through the formation ...

Article

Resonance Raman detection of the Fe2+-C-N modes in heme-copper oxidases: A probe of the active site

Pinakoulaki, Eftychia; Vamvouka, M.; Varotsis, Constantinos (2004)

Resonance Raman spectroscopy has been employed to investigate the reduced cyano complexes of cytochrome aa3 from bovine heart and Rhodobacter sphaeroides and of cytochrome bo3 from E. coli. In the aa 3-type oxidases, the ...

Article

Time-Resolved Resonance Raman and Time-Resolved Step-Scan FTIR Studies of Nitric Oxide Reductase from Paracoccus denitrificans: Comparison of the Heme b3-FeB Site to That of the Heme-CuB in Oxidases

Pinakoulaki, Eftychia; Varotsis, Constantinos (2003)

Time-resolved resonance Raman (TR3) and time-resolved step-scan (TRS2) FTIR spectroscopies have been used to probe the structural dynamics at the heme b3 proximal and distal sites after carbon monoxide photolysis from fully ...