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Salomonsson, Lina
Publications (6 of 6) Show all publications
Salomonsson, L., Reimann, J., Tosha, T., Krause, N., Gonska, N., Shiro, Y. & Ädelroth, P. (2012). Proton transfer in the quinol dependent nitric oxide reductase from geobacillus stearothermophilus during reduction of oxygen. Biochimica et Biophysica Acta - Bioenergetics, 1817(10), 1914-1920
Open this publication in new window or tab >>Proton transfer in the quinol dependent nitric oxide reductase from geobacillus stearothermophilus during reduction of oxygen
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2012 (English)In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1817, no 10, p. 1914-1920Article in journal (Refereed) Published
Abstract [en]

Bacterial nitric oxide reductases (NOR) are integral membrane proteins that catalyse the reduction of nitric oxide to nitrous oxide, often as a step in the process of denitrification. Most functional data has been obtained with NORs that receive their electrons from a soluble cytochrome c in the periplasm and are hence termed cNOR. Very recently, the structure of a different type of NOR, the quinol-dependent (q)-NOR from the thermophilic bacterium Geobacillus stearothermophilus was solved to atomic resolution [Y. Matsumoto, T. Tosha, A.V. Pisliakov, T. Hino, H. Sugimoto, S. Nagano, Y. Sugita and Y. Shiro, Nat. Struct. Mol. Biol. 19 (2012) 238-246]. In this study, we have investigated the reaction between this gNOR and oxygen. Our results show that, like some cNORs, the C. stearothermophilus gNOR is capable of 02 reduction with a turnover of similar to 3 electrons s(-1) at 40 degrees C. Furthermore, using the so-called flow-flash technique, we show that the fully reduced (with three available electrons) gNOR reacts with oxygen in a reaction with a time constant of 1.8 ms that oxidises the low-spin heme b. This reaction is coupled to proton uptake from solution and presumably forms a ferryl intermediate at the active site. The pH dependence of the reaction is markedly different from a corresponding reaction in cNOR from Paracoccus denitrificans, indicating that possibly the proton uptake mechanism and/or pathway differs between gNOR and cNOR. This study furthermore forms the basis for investigation of the proton transfer pathway in gNOR using both variants with putative proton transfer elements modified and measurements of the vectorial nature of the proton transfer. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).

Keywords
Heme-copper oxidase, Proton transfer pathway, Non-heme iron, Flow-flash, Carbon monoxide
National Category
Biochemistry and Molecular Biology
Research subject
Biochemistry
Identifiers
urn:nbn:se:su:diva-81832 (URN)10.1016/j.bbabio.2012.04.007 (DOI)000307918200028 ()
Note

AuthorCount:7;

Available from: 2012-11-07 Created: 2012-11-01 Last updated: 2022-02-24Bibliographically approved
Sanden, T., Salomonsson, L., Brzezinski, P. & Widengren, J. (2010). Surface-coupled proton exchange of a membrane-bound proton acceptor. Proceedings of the National Academy of Sciences of the United States of America, 107(9), 4129-4134
Open this publication in new window or tab >>Surface-coupled proton exchange of a membrane-bound proton acceptor
2010 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 107, no 9, p. 4129-4134Article in journal (Refereed) Published
Abstract [en]

Proton-transfer reactions across and at the surface of biological membranes are central for maintaining the transmembrane proton electrochemical gradients involved in cellular energy conversion. In this study, fluorescence correlation spectroscopy was used to measure the local protonation and deprotonation rates of single pH-sensitive fluorophores conjugated to liposome membranes, and the dependence of these rates on lipid composition and ion concentration. Measurements of proton exchange rates over a wide proton concentration range, using two different pH-sensitive fluorophores with different pK(a)s, revealed two distinct proton exchange regimes. At high pH (>8), proton association increases rapidly with increasing proton concentrations, presumably because the whole membrane acts as a proton-collecting antenna for the fluorophore. In contrast, at low pH (<7), the increase in the proton association rate is slower and comparable to that of direct protonation of the fluorophore from the bulk solution. In the latter case, the proton exchange rates of the two fluorophores are indistinguishable, indicating that their protonation rates are determined by the local membrane environment. Measurements on membranes of different surface charge and at different ion concentrations made it possible to determine surface potentials, as well as the distance between the surface and the fluorophore. The results from this study define the conditions under which biological membranes can act as proton-collecting antennae and provide fundamental information on the relation between the membrane surface charge density and the local proton exchange kinetics.

Keywords
biomembrane, diffusion, electrostatic potential, fluorescence correlation spectroscopy (FCS), proton transfer
National Category
Natural Sciences
Identifiers
urn:nbn:se:su:diva-50053 (URN)10.1073/pnas.0908671107 (DOI)000275131100035 ()
Note
authorCount :4Available from: 2011-01-03 Created: 2010-12-21 Last updated: 2022-02-24Bibliographically approved
Salomonsson, L., Brändén, G. & Brzezinski, P. (2008). Deuterium isotope effect of proton pumping in cytochrome c oxidase. Biochimica et Biophysica Acta - Bioenergetics, 1777(4), 343-350
Open this publication in new window or tab >>Deuterium isotope effect of proton pumping in cytochrome c oxidase
2008 (English)In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1777, no 4, p. 343-350Article in journal (Refereed) Published
Abstract [en]

In mitochondria and many aerobic bacteria cytochrome c oxidase is the terminal enzyme of the respiratory chain where it catalyses the reduction of oxygen to water. The free energy released in this process is used to translocate (pump) protons across the membrane such that each electron transfer to the catalytic site is accompanied by proton pumping. To investigate the mechanism of electron–proton coupling in cytochrome c oxidase we have studied the pH-dependence of the kinetic deuterium isotope effect of specific reaction steps associated with proton transfer in wild-type and structural variants of cytochrome c oxidases in which amino-acid residues in proton-transfer pathways have been modified. In addition, we have solved the structure of one of these mutant enzymes, where a key component of the proton-transfer machinery, Glu286, was modified to an Asp. The results indicate that the P3 → F3 transition rate is determined by a direct proton-transfer event to the catalytic site. In contrast, the rate of the F3 → O4 transition, which involves simultaneous electron transfer to the catalytic site and is characteristic of any transition during CytcO turnover, is determined by two events with similar rates and different kinetic isotope effects. These reaction steps involve transfer of protons, that are pumped, via a segment of the protein including Glu286 and Arg481.

Keywords
Cytochrome aa3, Electron transfer, Proton transfer, Membrane protein, Transmembrane transport, Kinetics, Spectroscopy, Mitochondria
National Category
Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:su:diva-14857 (URN)10.1016/j.bbabio.2007.09.009 (DOI)000255503400003 ()18371493 (PubMedID)
Available from: 2008-11-05 Created: 2008-11-05 Last updated: 2022-03-18Bibliographically approved
Faxén, K., Salomonsson, L., Ädelroth, P. & Brzezinski, P. (2006). Inhibition of proton pumping by zinc ions during specific reaction steps in cytochrome c oxidase.. Biochim Biophys Acta, 1757(5-6), 388-94
Open this publication in new window or tab >>Inhibition of proton pumping by zinc ions during specific reaction steps in cytochrome c oxidase.
2006 (English)In: Biochim Biophys Acta, ISSN 0006-3002, Vol. 1757, no 5-6, p. 388-94Article in journal (Refereed) Published
Keywords
Biological Transport, Catalytic Domain, Cations; Divalent, Electron Transport, Electron Transport Complex IV/antagonists & inhibitors/*chemistry, Oxidation-Reduction, Oxygen/chemistry, Phospholipids/chemistry, Proton Pumps/antagonists & inhibitors/*chemistry, Protons, Rhodobacter sphaeroides/*enzymology, Zinc/pharmacology
Identifiers
urn:nbn:se:su:diva-19220 (URN)16806055 (PubMedID)
Available from: 2007-10-23 Created: 2007-10-23 Last updated: 2022-02-25Bibliographically approved
Busenlehner, L. S., Salomonsson, L., Brzezinski, P. & Armstrong, R. N. (2006). Mapping protein dynamics in catalytic intermediates of the redox-driven proton pump cytochrome c oxidase.. Proc Natl Acad Sci U S A, 103(42), 15398-403
Open this publication in new window or tab >>Mapping protein dynamics in catalytic intermediates of the redox-driven proton pump cytochrome c oxidase.
2006 (English)In: Proc Natl Acad Sci U S A, ISSN 0027-8424, Vol. 103, no 42, p. 15398-403Article in journal (Refereed) Published
Keywords
Biological Transport/physiology, Deuterium/chemistry/metabolism, Electron Transport Complex IV/*chemistry/genetics/*metabolism, Hydrogen/chemistry/metabolism, Mass Spectrometry, Oxidation-Reduction, Protein Structure; Tertiary, Protein Subunits/chemistry/genetics/metabolism, Protons, Rhodobacter sphaeroides/metabolism
Identifiers
urn:nbn:se:su:diva-19217 (URN)17023543 (PubMedID)
Available from: 2007-10-23 Created: 2007-10-23 Last updated: 2022-02-25Bibliographically approved
Salomonsson, L., Faxén, K., Ädelroth, P. & Brzezinski, P. (2005). The timing of proton migration in membrane-reconstituted cytochrome c oxidase.. Proc Natl Acad Sci U S A, 102(49), 17624-9
Open this publication in new window or tab >>The timing of proton migration in membrane-reconstituted cytochrome c oxidase.
2005 (English)In: Proc Natl Acad Sci U S A, ISSN 0027-8424, Vol. 102, no 49, p. 17624-9Article in journal (Other academic) Published
Keywords
Detergents/pharmacology, Electron Transport Complex IV/*chemistry/*metabolism, Lipids/chemistry, Models; Molecular, Protein Structure; Quaternary, Protons, Rhodobacter sphaeroides/*enzymology, Solutions, Time Factors
Identifiers
urn:nbn:se:su:diva-19224 (URN)16306266 (PubMedID)
Available from: 2007-10-23 Created: 2007-10-23 Last updated: 2022-02-25Bibliographically approved
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