A haloarchaeal ferredoxin electron donor that plays an essential role in nitrate assimilation. (21st November 2011)

• Record Type: Journal Article
• Authors: Zafrilla, Basilio; Martínez-Espinosa, Rosa María; Bonete, María José; Butt, Julea N.; Richardson, David J.; Gates, Andrew J.
• Is Part Of: Biochemical Society transactions. Volume 39:Number 6(2011)
• Page Start: 1844
• Page End: 1848
• Publication Date: 2011-11-21
• Subjects: ferredoxin -- haloarchaeon -- nitrate assimilation -- nitrate and nitrite reduction; Biochemistry -- Congresses; 572
• DOI: 10.1042/BST20110709
• Languages: English
• ISSNs: 0300-5127

Abstract

Abstract : In the absence of ammonium, many organisms, including the halophilic archaeon Haloferax volcanii DS2 (DM3757), may assimilate inorganic nitrogen from nitrate or nitrite, using a ferredoxin-dependent assimilatory NO3 − /NO2 − reductase pathway. The small acidic ferredoxin Hv -Fd plays an essential role in the electron transfer cascade required for assimilatory nitrate and nitrite reduction by the cytoplasmic NarB- and NirA-type reductases respectively. UV–visible absorbance and EPR spectroscopic characterization of purified Hv -Fd demonstrate that this protein binds a single [2Fe–2S] cluster, and potentiometric titration reveals that the cluster shares similar redox properties with those present in plant-type ferredoxins.