The photosynthetic cytochrome c550 from the diatom Phaeodactylum tricornutum

  • Pilar Bernal-Bayard
  • Leonor Puerto-Galán
  • Inmaculada Yruela
  • Inés García-Rubio
  • Carmen Castell
  • José M. Ortega
  • Pablo J. Alonso
  • Mercedes Roncel
  • Jesús I. Martínez
  • Manuel Hervás
  • José A. Navarro
Original Article

DOI: 10.1007/s11120-016-0327-x

Cite this article as:
Bernal-Bayard, P., Puerto-Galán, L., Yruela, I. et al. Photosynth Res (2016). doi:10.1007/s11120-016-0327-x


The photosynthetic cytochrome c550 from the marine diatom Phaeodactylum tricornutum has been purified and characterized. Cytochrome c550 is mostly obtained from the soluble cell extract in relatively large amounts. In addition, the protein appeared to be truncated in the last hydrophobic residues of the C-terminus, both in the soluble cytochrome c550 and in the protein extracted from the membrane fraction, as deduced by mass spectrometry analysis and the comparison with the gene sequence. Interestingly, it has been described that the C-terminus of cytochrome c550 forms a hydrophobic finger involved in the interaction with photosystem II in cyanobacteria. Cytochrome c550 was almost absent in solubilized photosystem II complex samples, in contrast with the PsbO and Psb31 extrinsic subunits, thus suggesting a lower affinity of cytochrome c550 for the photosystem II complex. Under iron-limiting conditions the amount of cytochrome c550 decreases up to about 45% as compared to iron-replete cells, pointing to an iron-regulated synthesis. Oxidized cytochrome c550 has been characterized using continuous wave EPR and pulse techniques, including HYSCORE, and the obtained results have been interpreted in terms of the electrostatic charge distribution in the surroundings of the heme centre.


Cytochrome c550 Phaeodactylum Photosystem II EPR Hemeprotein 





Cytochrome c550


Cytochrome c6


Continuous wave


Electron paramagnetic resonance


Hyperfine sublevel correlation spectroscopy


Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry


Photosystem II

Supplementary material

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Supplementary material 1 (TIFF 23191 KB)
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Supplementary material 2 (TIFF 17867 KB)
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Supplementary material 3 (TIFF 17988 KB)
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Supplementary material 4 (TIFF 17738 KB)

Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la CartujaUniversidad de Sevilla & CSICSevillaSpain
  2. 2.Estación Experimental de Aula Dei, EEAD-CSICZaragozaSpain
  3. 3.Centro Universitario de la DefensaZaragozaSpain
  4. 4.Laboratory of Physical ChemistryETH ZurichZurichSwitzerland
  5. 5.Instituto de Ciencia de Materiales de AragónUniversidad de Zaragoza & CSICZaragozaSpain

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