Plant Molecular Biology

, Volume 44, Issue 2, pp 231–243

Arabidopsis ATP A2 peroxidase. Expression and high-resolution structure of a plant peroxidase with implications for lignification

  • Lars Østergaard
  • Kaare Teilum
  • Osman Mirza
  • Ole Mattsson
  • Morten Petersen
  • Karen G. Welinder
  • John Mundy
  • Michael Gajhede
  • Anette Henriksen
Article

DOI: 10.1023/A:1006442618860

Cite this article as:
Østergaard, L., Teilum, K., Mirza, O. et al. Plant Mol Biol (2000) 44: 231. doi:10.1023/A:1006442618860

Abstract

Lignins are phenolic biopolymers synthesized by terrestrial, vascular plants for mechanical support and in response to pathogen attack. Peroxidases have been proposed to catalyse the dehydrogenative polymerization of monolignols into lignins, although no specific isoenzyme has been shown to be involved in lignin biosynthesis. Recently we isolated an extracellular anionic peroxidase, ATP A2, from rapidly lignifying Arabidopsis cell suspension culture and cloned its cDNA. Here we show that the Atp A2 promoter directs GUS reporter gene expression in lignified tissues of transgenic plants. Moreover, an Arabidopsis mutant with increased lignin levels compared to wild type shows increased levels of ATP A2 mRNA and of a mRNA encoding an enzyme upstream in the lignin biosynthetic pathway. The substrate specificity of ATP A2 was analysed by X-ray crystallography and docking of lignin precursors. The structure of ATP A2 was solved to 1.45 Å resolution at 100 K. Docking of p-coumaryl, coniferyl and sinapyl alcohol in the substrate binding site of ATP A2 were analysed on the basis of the crystal structure of a horseradish peroxidase C-CN-ferulic acid complex. The analysis indicates that the precursors p-coumaryl and coniferyl alcohols are preferred by ATP A2, while the oxidation of sinapyl alcohol will be sterically hindered in ATP A2 as well as in all other plant peroxidases due to an overlap with the conserved Pro-139. We suggest ATP A2 is involved in a complex regulation of the covalent cross-linking in the plant cell wall.

Arabidopsis thalianalignificationmonolignolsplant peroxidasepromoterX-ray structure

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • Lars Østergaard
    • 1
  • Kaare Teilum
    • 2
  • Osman Mirza
    • 3
  • Ole Mattsson
    • 1
  • Morten Petersen
    • 1
  • Karen G. Welinder
    • 2
  • John Mundy
    • 1
  • Michael Gajhede
    • 3
  • Anette Henriksen
    • 3
  1. 1.Department of Plant Physiology, Institute of Molecular BiologyUniversity of Copenhagen, ØKøbenhavn KDenmark
  2. 2.Department of Protein Chemistry, Institute of Molecular BiologyUniversity of Copenhagen, ØKøbenhavn KDenmark
  3. 3.Protein Structure Group, Department of ChemistryUniversity of CopenhagenKøbenhavn ØDenmark