JBIC Journal of Biological Inorganic Chemistry

, Volume 10, Issue 2, pp 156–166

Vanadium-dependent iodoperoxidases in Laminaria digitata, a novel biochemical function diverging from brown algal bromoperoxidases

Authors

  • Carole Colin
    • Station Biologique, UMR 7139 CNRSGoëmar-Université Pierre & Marie Curie
  • Catherine Leblanc
    • Station Biologique, UMR 7139 CNRSGoëmar-Université Pierre & Marie Curie
  • Gurvan Michel
    • Station Biologique, UMR 7139 CNRSGoëmar-Université Pierre & Marie Curie
  • Elsa Wagner
    • Laboratoire de Spectrométrie de Masse Bio-Organique, UMR 7509CNRS-Université Louis Pasteur
  • Emmanuelle Leize-Wagner
    • Laboratoire de Spectrométrie de Masse Bio-Organique, UMR 7509CNRS-Université Louis Pasteur
  • Alain Van Dorsselaer
    • Laboratoire de Spectrométrie de Masse Bio-Organique, UMR 7509CNRS-Université Louis Pasteur
    • Station Biologique, UMR 7139 CNRSGoëmar-Université Pierre & Marie Curie
Original Article

DOI: 10.1007/s00775-005-0626-8

Cite this article as:
Colin, C., Leblanc, C., Michel, G. et al. J Biol Inorg Chem (2005) 10: 156. doi:10.1007/s00775-005-0626-8

Abstract

The brown alga Laminaria digitata features a distinct vanadium-dependent iodoperoxidase (vIPO) activity, which has been purified to electrophoretic homogeneity. Steady-state analyses at pH 6.2 are reported for vIPO (K m I− =2.5 mM; k cat I− =462 s−1) and for the previously characterised vanadium-dependent bromoperoxidase in L. digitata (K m I− =18.1 mM; k cat I− =38 s−1). Although the vIPO enzyme specifically oxidises iodide, competition experiments with halides indicate that bromide is a competitive inhibitor with respect to the fixation of iodide. A full-length complementary ANA (cDNA) was cloned and shown to be actively transcribed in L. digitata and to encode the vIPO enzyme. Mass spectrometry analyses of tryptic digests of vIPO indicated the presence of at least two very similar proteins, in agreement with Southern analyses showing that vIPOs are encoded by a multigenic family in L. digitata. Phylogenetic analyses indicated that vIPO shares a close common ancestor with brown algal vanadium-dependent bromoperoxidases. Based on a three-dimensional structure model of the vIPO active site and on comparisons with those of other vanadium-dependent haloperoxidases, we propose a hypothesis to explain the evolution of strict specificity for iodide in L. digitata vIPO.

Keywords

Vanadium Haloperoxidase Iodoperoxidase Halide specificity Laminaria digitata

Abbreviations

bp

base pair

BPO

Bromoperoxidase

cDNA

Complementary DNA

CPO

Chloroperoxidase

HPO

Haloperoxidase

IPO

Iodoperoxidase

LC

Liquid chromatography

mRNA

Messenger RNA

MS/MS

Tandem mass spectrometry

PAGE

Polyacrylamide gel electrophoresis

PCR

Polymerase chain reaction

RACE

Rapid amplification of cDNA ends

SDS

Sodium dodecyl sulphate

SSC

Saline–sodium citrate

UTR

Untranslated region

vBPO

Vanadium-dependent BPO

vCPO

Vanadium-dependent CPO

vHPO

Vanadium-dependent HPO

vIPO

Vanadium-dependent IPO

Copyright information

© SBIC 2005