Cloning and characterisation of a hyp gene cluster in the filamentous cyanobacterium Nostoc sp. strain PCC 73102

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 N-2-Fixing but nor under non-N-2-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. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.