Methods for Nitrogenase-Like Dark Operative Protochlorophyllide Oxidoreductase

  • Jürgen MoserEmail author
  • Markus J. Bröcker
Part of the Methods in Molecular Biology book series (MIMB, volume 766)


Nitrogenase-like dark operative protochlorophyllide oxidoreductase (DPOR) is involved in the biosynthesis of chlorophylls and bacteriochlorophylls in gymnosperms, ferns, algae, and photosynthetic bacteria. During protochlorophyllide (Pchlide) reduction, the homodimeric subunit ChlL2 of DPOR transfers electrons on the corresponding heterotetrameric catalytic subunit (ChlN/ChlB)2. Although DPOR shares significant amino acid sequence homology to the nitrogenase system, only the initial catalytic steps of DPOR resemble nitrogenase catalysis. Investigation of the cyanobacterial DPOR from Prochlorococcus marinus indicated that subcomplex ChlL2 is functioning as an ATP-dependent switch protein, triggering the transient interaction of ChlL2 and (ChlN/ChlB)2. This dynamic subunit interplay is responsible for the transfer of a single electron from the [4Fe–4S] cluster of ChlL2 onto a second [4Fe–4S] cluster located on (ChlN/ChlB)2. However, the second part of DPOR catalysis is unrelated to nitrogenase catalysis, since no molybdenum-containing cofactor or a P-cluster equivalent is employed. Instead, two consecutive electron transfer steps are mediated via the [4Fe–4S] cluster of (ChlN/ChlB)2, resulting in the reduction of the conjugated ring system of the substrate molecule Pchlide (Figs. 5.1a and 5.2).

Key words

Dark operative protochlorophyllide oxidoreductase (DPOR) nitrogenase-like enzyme chlorophyll biosynthesis dynamic switch protein 


  1. 1.
    Bröcker MJ, Virus S, Ganskow S et al (2008) ATP-driven reduction by dark-operative protochlorophyllide oxidoreductase from chlorobium tepidum mechanistically resembles nitrogenase catalysis. J Biol Chem 283:10559–10567PubMedCrossRefGoogle Scholar
  2. 2.
    Bröcker MJ, Wätzlich D, Uliczka F et al (2008) Substrate recognition of nitrogenase-like dark operative protochlorophyllide oxidoreductase from Prochlorococcus marinus. J Biol Chem 283:29873–29881PubMedCrossRefGoogle Scholar
  3. 3.
    Brocker MJ, Waetzlich D, Saggu M et al (2010) Biosynthesis of (bacterio)chlorophylls: ATP-dependent transient subunit interaction and electron transfer of dark operative protochlorophyllide oxidoreductase. J Biol Chem 285:8268–8277PubMedCrossRefGoogle Scholar
  4. 4.
    Walther J, Bröcker MJ, Wätzlich D et al (2009) Protochlorophyllide: a new photosensitizer for the photodynamic inactivation of Gram-positive and Gram-negative bacteria. FEMS Microbiol Lett 290:156–163PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Institut für Mikrobiologie, Technische Universität BraunschweigBraunschweigGermany

Personalised recommendations