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Electron-proton coupling in electron transfer proteins

Electron-proton coupling in electron transfer proteins

Quite a number of biologically relevant processes are mediated by the coupling of proton and electron transfer within the protein matrix. Mitochondrial respiration and photosynthesis are examples of that. Thermodynamic coupling between electron and proton transfer is also present in small proteins, like cytochromes c3. These systems are more prone to be studied by modelling methodologies since they are smaller. We have done a lot of research on the Redox-Bohr effect present on cytochromes c3, using proteins from several origins.

correlation

Correlation between total reduction and total protonation at different values of pH and E. High correlations are an indication of coupling between electrons and protons and a signature of the Redox-Bohr effect


References:

  • Baptista, A.M., Martel, P.J., Soares, C.M. (1999) "Simulation of electron-proton coupling with a Monte Carlo method: application to cytochrome c3 using continuum electrostatics", Biophys.J., 76, 2978-2998
  • Louro, R.O., Bento, I., Matias, P.M., Catarino, T., Baptista, A.M., Soares, C.M., Carrondo, M.A., Turner, D.L., Xavier, A.V. (2001) "Conformational component in the coupled transfer of multiple electrons and protons in a monomeric tetrahaem cytochrome" J.Biol.Chem., 276, 44044-44051
  • Teixeira, V.H., Soares, C.M., Baptista, A.M. (2002) "Studies of the reduction and protonation behaviour of tetrahaem cytochromes using atomic detail", JBIC, 7, 200-216
  • Bento, I., Teixeira, V.H., Baptista, A.M., Soares, C.M., Matias, P.M., Carrondo, M.A. (2003) "Redox-Bohr and other cooperativity effects in the nine-heme cytochrome c from Desulfovibrio desulfuricans ATCC 27774: crystallographic and modeling studies", J.Biol.Chem., 278, 36455-36469
  • Bento, I., Matias, P.M., Baptista, A.M., da Costa, P.N., van Dongen, W.M.A.M., Saraiva, L.M., Schneider, T.R., Soares, C.M., Carrondo, M.A. (2004) "Molecular basis for redox-Bohr and cooperative effects in cytochrome c3 from Desulfovibrio desulfuricans ATCC 27774: crystallographic and modeling studies of oxidised and reduced high-resolution structures at pH 7.6", Proteins, 54, 135-152


Proton binding thermodynamics in the P.denitrificans aa3 and in the R.marinus caa3 haem-copper oxygen reductases - Understanding proton pumping



 
                                     Paracocus denitrificans cytochrome aa3



 
                                     Glu 278A is proton active at physiological pH



                               Rhodobacter marinus cytochrome caa3 (model)

 
The spatial substitute of Glu 278A in caa3 (Tyr 256A) is proton inactive at physiological pH


In collaboration with the group of Miguel Teixeira.


Work references:

  • Pereira, M.M., Santana, M., Soares, C.M., Mendes, J., Carita, J.N., Saraste, M., Carrondo, M.A., Teixeira, M. (1999) "The caa3 terminal oxidase of the thermohalophilic bacterium Rhodothermus marinus", BBA, 1413, 1-13.
  • Santana, M., Pereira, M.M., Elias, N.P., Soares, C.M., Teixeira, M. (2001) "The genes encoding Rhodothermus marinus HiPiP: oxygen oxidoreductase, a caa3-type oxidase belonging to the superfamily of membrane heme-copper oxidases", J. Bacteriology,183, 687-699
  • Soares, C.M., Baptista, A.M., Pereira, M.M., Teixeira, M. (2004) "Investigation of protonable residues in Rhodothermus marinus caa3 haem-copper oxygen reductase: comparison with Paracoccus denitrificans aa3 haem-copper oxygen reductase", JBIC, 9, 124-134

 

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