Sequence and electron paramagnetic resonance analyses of nitrate reductase NarGH from a denitrifying halophilic
Katsuhiko Yoshimatsu1, Toshio Iwasaki, Taketomo Fujiwara
1Department of Biology and Geosciences, Faculty of Science, Shizuoka University, 836 Ohya, 422-8529, Shizuoka, Japan.
Abstract:
Genes encoding the NarG and NarH subunits of the molybdo-iron-sulfur enzyme, a nitrate reductase from a denitrifying halophilic euryarchaeota Haloarcula marismortui, were cloned and sequenced. An incomplete cysteine motif reminiscent of that for a [4Fe-4S] cluster binding was found in the NarG subunit, and complete cysteine arrangements for binding one [3Fe-4S] cluster and three [4Fe-4S] clusters were found in the NarH subunit. In conjunction with chemical, electron paramagnetic resonance, and subcellular localization analyses, we firmly establish that the H. marismortui enzyme is a new archaeal member of the known membrane-bound nitrate reductases whose homologs are found in the bacterial domain.
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