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Molecular and General Genetics MGG

, Volume 254, Issue 4, pp 433–439 | Cite as

Indolepyruvate ferredoxin oxidoreductase from Pyrococcus sp. KOD1 possesses a mosaic structure showing features of various oxidoreductases

  • M. A. Siddiqui
  • S. Fujiwara
  • T. Imanaka
ORIGINAL PAPER

Abstract

Indolepyruvate ferredoxin oxidoreductase (IOR) catalyzes the oxidative decarboxylation of arylpyruvates. Gene cloning and sequencing analysis of the IOR gene from the hyperthermophilic archaeon Pyrococcus sp. KOD1 was performed. Two genes, iorA and iorB, encoding α and β subunits of IOR were found to be tandemly arranged, which suggests that gene expression is translationaly coupled. Sequence analysis showed the C-terminal region of the α subunit to have a typical ferredoxin-type [4Fe-4S] cluster motif (CXXCXXCXXCXXXCP), which is similar to that present in the δ subunits of other oxidoreductases such as pyruvate ferredoxin oxidoreductase (POR) and 2-ketoisovalerate ferredoxin oxidoreductase (VOR). We suggest that the α subunit of KOD1-IOR has a mosaic structure composed of features characteristic of the α, β and δ subunits from POR and VOR. KOD1-IOR was overproduced in anaerobically incubated Escherichia coli cells and the crude enzyme was extracted under anaerobic conditions. The optimal temperature for activity of recombinant IOR was 70° C and the half-life of this enzyme in the presence of air was 15 min at 25° C.

Key words Indolepyruvate ferredoxin oxido- reductase  Aromatic amino acids   [4Fe-4S] cluster  Archaea   Evolution 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • M. A. Siddiqui
    • 1
  • S. Fujiwara
    • 1
  • T. Imanaka
    • 2
  1. 1.Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka 565, JapanJP
  2. 2.Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-01, JapanJP

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