Browsing by Author "Pinakoulaki, Eftychia"
Now showing items 1-20 of 43
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The Active Site Structure of Heme a3 3+-C≡N-CuB2+ of Cytochrome aa 3 Oxidase as Revealed from Resonance Raman Scattering
Pinakoulaki, Eftychia; Vamvouka, M.; Varotsis, Constantinos (2003)Resonance Raman and FTIR spectroscopies have been employed to investigate the structure of the heme a3-C≡N-CuB complex of oxidized cytochrome aa3 oxidase. The characterization of this complex is essential since a central ...
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Aldoxime dehydratase: Probing the heme environment involved in the synthesis of the carbon-nitrogen triple bond
Pinakoulaki, Eftychia; Koutsoupakis, Constantinos; Sawai, H.; Pavlou, A.; Kato, Y.; Asano, Y.; Aono, S. (2011)Fourier transform infrared (FTIR) spectra, "light" minus "dark" difference FTIR spectra, and time-resolved step-scan (TRS 2) FTIR spectra are reported for carbonmonoxy aldoxime dehydratase. Two C-O modes of heme at 1945 ...
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Carob as cocoa substitute: a review on composition, health benefits and food applications
Loullis, Andreas; Pinakoulaki, Eftychia (2018)Cocoa originates from the beans of the cocoa tree (Theobroma cacao L.). It is an important commodity and the main ingredient in chocolate manufacture. Its value and quality are related to complex flavors and to its distinct ...
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Coupling of helix E-F motion with the O-nitrito and 2-nitrovinyl coordination in myoglobin
Ioannou, Androulla; Lambrou, Alexandra; Daskalakis, Vangelis; Pinakoulaki, Eftychia (2017)Myoglobin (Mb) is known to react slowly with nitirite to form the green pigment by NO2 − cordination to the heme Fe in the O-binding nitrito (O1[sbnd]N[dbnd]O2) mode and to the heme 2-vinyl position. Nitrite is a powerful ...
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Decay of the transient CuB-CO complex is accompanied by formation of the heme Fe-CO complex of cytochrome cbb3-CO at ambient temperature: Evidence from time-resolved fourier transform infrared spectroscopy
Stavrakis, Stavros; Koutsoupakis, Constantinos; Pinakoulaki, Eftychia; Urban, A.; Saraste, M.; Varotsis, Constantinos (2002)Time-resolved step-scan Fourier infrared spectroscopy has been used to study the CO-bound cbb3-type cytochrome c oxidase from Pseudomonas stutzeri at room temperature. We observe a single band in the FTIR spectrum at 1956 ...
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Detection of a photostable five-coordinate heme a3-Fe-Co species and functional implications of His384/α10 in CO-bound ba 3-cytochrome c oxidase from Thermus thermophilus
Ohta, T.; Pinakoulaki, Eftychia; Soulimane, T.; Kitagawa, T.; Varotsis, Constantinos (2004)Resonance Raman (RR) spectra are reported for the fully reduced carbon monoxy derivative of ba3-cytochrome c oxidase from Thermus thermophilus. The RR spectra show the formation of a photolabile six-coordinate heme-CO and ...
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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 ...
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Direct detection of Fe(IV)=O intermediates in the cytochrome aa3 oxidase from Paracoccus denitrificans[H2O2 reaction
Pinakoulaki, Eftychia; Pfitzner, U.; Ludwig, B.; Varotsis, Constantinos (2003)We report the first evidence for the formation of the "607- and 580-nm forms" in the cytochrome oxidase aa3/H2O2 reaction without the involvement of tyrosine 280. The pKa of the 607-580-nm transition is 7.5. The 607-nm ...
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Erratum to "ICPBCZin: A red emitting ratiometric fluorescent indicator with nanomolar affinity for Zn2+ ions" [Cell Calcium 44 (3) (2008) 270-275] (DOI:10.1016/j.ceca.2007.12.008)
Roussakis, E.; Voutsadaki, S.; Pinakoulaki, Eftychia; Sideris, D. P.; Tokatlidis, K.; Katerinopoulos, H. E. (2009)
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Evidence for the presence of two conformations of the heme a 3-CuB pocket of cytochrome caa 3 from Thermus thermophilus
Pavlou, A.; Soulimane, T.; Pinakoulaki, Eftychia (2011)Resonance Raman (RR) and "light" minus "dark" Fourier transform infrared (FTIR) difference spectra are reported for the CO-bound caa3 oxidase from Thermus thermophilus. Two Fe-CO stretching modes at 518 and 507 cm-1, the ...
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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 ...
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Fourier transform infrared evidence for a ferric six-coordinate nitrosylheme b3 complex of cytochrome cbb3 oxidase from Pseudomonas stutzeri at ambient temperature
Stavrakis, Stavros; Pinakoulaki, Eftychia; Urbani, A.; Varotsis, Constantinos (2002)We report the first vibrational study of NO bound to an oxidized heme-copper oxidase. Cytochrome cbb3 oxidase from P. stutzeri reduces both O2 and NO to H2O and N2O, respectively. The ferric nitrosyl complex of cbb3 exhibits ...
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ICPBCZin: A red emitting ratiometric fluorescent indicator with nanomolar affinity for Zn2+ ions
Roussakis, E.; Voutsadaki, S.; Pinakoulaki, Eftychia; Sideris, D. P.; Tokatlidis, K.; Katerinopoulos, H. E. (2008)A new fluorescent Zn2+ indicator, namely, ICPBCZin was synthesized and the spectral profile of its free and Zn2+ bound forms was studied. The newly synthesized zinc indicator incorporates as chromophore the chromeno ...
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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 ...
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Nitric-oxide reductase: Structure and properties of the catalytic site from resonance Raman scattering
Pinakoulaki, Eftychia; Gemeinhardt, S.; Saraste, M.; Varotsis, Constantinos (2002)We have applied resonance Raman spectroscopy to investigate the properties of the dinuclear center of oxidized, reduced, and NO-bound nitric-oxide reductase from Paracoccus denitrificans. The spectra of the oxidized enzyme ...
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Nitrite coordination in myoglobin
Ioannou, Androulla; Lambrou, Alexandra; Daskalakis, Vangelis; Pinakoulaki, Eftychia (2017)The coordination of nitrite in myoglobin (Mb) has been characterized by resonance Raman spectroscopy and the frequencies of the nitrite bound to the heme Fe as well to the 2-vinyl have been computed by density functional ...
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Observation of ligand transfer in ba 3 oxidase from thermus thermophilus: Simultaneous FTIR detection of photolabile heme a 3 2+-CN and transient CuB 2+-CN complexes
Loullis, Andreas; Noor, M. R.; Soulimane, T.; Pinakoulaki, Eftychia (2012)FTIR and light-minus-dark FTIR spectroscopy have been employed to investigate the reaction of oxidized and fully reduced ba3 oxidase with cyanide. The characterization of the structures of the bound CN- in the binuclear ...
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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 ...
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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 ...
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Probing nitrite coordination in horseradish peroxidase by resonance Raman spectroscopy: Detection of two binding sites
Ioannou, Androulla; Pinakoulaki, Eftychia (2017)Nitrite is a powerful oxidant that affects the activity of peroxidases towards various substrates and leads to heme macrocycle modifications in members of the peroxidase family, such as the horseradish peroxidase (HRP). ...