Planta

, Volume 227, Issue 2, pp 353–362

The genome of the thermoacidophilic red microalga Galdieria sulphuraria encodes a small family of secreted class III peroxidases that might be involved in cell wall modification

  • C. Oesterhelt
  • S. Vogelbein
  • R. P. Shrestha
  • M. Stanke
  • A. P. M. Weber
Original Article
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Abstract

We report the identification of a small family of secreted class III plant peroxidases (Prx) from the genome of the unicellular thermoacidophilic red alga Galdieria sulphuraria (Cyanidiaceae). Apart from two class I ascorbate peroxidases and one cytochrome c peroxidase, the red algal genome encodes four class III plant peroxidases, thus complementing the short list of algal cell wall peroxidases (Passardi et al. in Genomics 89:567–579, 2007). We have characterized the family gene structure, analyzed the extracellular space and cell wall fraction of G. sulphuraria for the presence of peroxidase activity and used shotgun proteomics to identify candidate extracellular peroxidases. For a detailed enzymatic characterization, we have purified a secreted peroxidase (GsPrx04) from the cell-free medium using hydrophobic interaction chromatography. The enzyme proved heat and acid-stable and exhibited an apparent molecular mass of 40 kDa. Comparative genomics between endolithically growing G. sulphuraria and a close relative, the obligatory aquatic, cell wall-less Cyanidioschyzon merolae, revealed that class III peroxidases only occur in the terrestrial microalga, thus supporting the key function of these enzymes in the process of land colonization.

Keywords

Cell wall Cyanidiaceae Galdieria Plant peroxidase Rhodophyta 

Abbreviation

Prx

Peroxidase

Supplementary material

425_2007_622_MOESM1_ESM.pdf (18 kb)
Fig. S1 Neighbour-joining tree of class I and class III peroxidases. The phylogenetic tree was constructed from derived protein sequences using the ClustalW and Phylip services at the Institut Pasteur (http://www.pasteur.fr/english.html). Bootstrap values are indicated on the branches. Galdieria sulphuraria sequences, generated in this study, are indicated by an asterisk. Proteins from organisms other than G. sulphuraria were taken from the PeroxiBase (http://peroxidase.isb-sib.ch/; Bakolovic et al. 2006). For those proteins available at NCBI (http://www.ncbi.nlm.nih.gov/), the corresponding accession numbers are also given in parentheses. AruPrx01a (AAA33377) corresponds to horseradish peroxidase HRP C1, generally used as reference for class III peroxidases. The putative cytochrome c peroxidase from G. sulphuraria (GsuCcP01) was used as an outgroup (PDF 17 kb)

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • C. Oesterhelt
    • 1
  • S. Vogelbein
    • 2
    • 5
  • R. P. Shrestha
    • 3
  • M. Stanke
    • 4
  • A. P. M. Weber
    • 3
    • 6
  1. 1.Institut für Biochemie und BiologieUniversität PotsdamPotsdam-GolmGermany
  2. 2.Institut für BiologieFreie Universität BerlinBerlinGermany
  3. 3.Department of Plant Biology Michigan State UniversityEast LansingUSA
  4. 4.Institut für Mikrobiologie und GenetikGeorg-August-Universität GöttingenGöttingenGermany
  5. 5.Leibniz-Institut für Molekulare PharmakologieBerlinGermany
  6. 6.Institut für Biochemie der PflanzenHeinrich-Heine-UniversitätDüsseldorfGermany

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