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Abstract
Maturation of [NiFe]-hydrogenases requires the action of several groups of accessory genes. Homologues of one group of these genes, the so-called hyp genes, putatively encoding proteins participating in the formation of an active uptake hydrogenase in the filamentous, heterocyst-forming cyanobacterium Nostoc PCC 73102, were cloned. The cluster, consisting of hypF, hypC, hypD, hypE, hypA, and hypB, is located 3.8 kb upstream from the uptake hydrogenase-encoding hupSL. Gene expression analyses show that these hyp genes are, like hupL, transcribed under N2-fixing but not under non-N2-fixing growth conditions. Furthermore, the six hyp genes are transcribed together with an open reading frame upstream of hypF, as a single mRNA. Analysis of the DNA region upstream of the experimentally determined transcriptional start site revealed putative −10 and −35 sequence elements and putative binding sites for the global nitrogen regulator NtcA.
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1 Department of Physiological Botany, EBC, Uppsala University, Villavägen 6, SE-752 36 Uppsala, Sweden; Molecular and Cellular Biophysics Research Unit, Medical Faculty of the Friedrich-Schiller University, Drackendorfer Strasse 1, D-07747 Jena, Germany
2 Department of Physiological Botany, EBC, Uppsala University, Villavägen 6, SE-752 36 Uppsala, Sweden
3 Department of Physiological Botany, EBC, Uppsala University, Villavägen 6, SE-752 36 Uppsala, Sweden; Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142292, Russia