Sequence of a 10.5 kbp fragment of Clostridium pasteurianum genomic DNA encompassing the hydrogenase I gene and two spore germination genes.
The gene encoding hydrogenase I from Clostridium pasteurianum had previously been cloned and sequenced as part of a 2.3 kbp Sau3A genomic DNA fragment. The analysis of the regions surrounding the hydrogenase gene has been extended by cloning and sequencing two EcoRI fragments, both partially overlapping the 2.3 kbp Sau3A fragment. An uninterrupted genomic sequence of 10.5 kbp has thus been obtained, including 6.7 kbp upstream of the hydrogenase gene, and 2 kbp downstream. The hydrogenase gene is separated by 473 bp from the next open reading frame on its 5' side and by 366 bp from the next open reading frame on its 3' side. It is preceded by putative promoter regions, and followed by a strong transcription termination signal. Therefore the hydrogenase I gene from C. pasteurianum probably belongs to a monocistronic operon. This is consistent with previous biochemical evidence showing that the enzyme is monomeric. The sequence data also show that in the case of this Fe-hydrogenase, in contrast to the NiFe-hydrogenases, there are no accessory genes cotranscribed with, or located near, the structural genes. The sequenced region contains six open reading frames in addition to the hydrogenase gene. One of these probably encodes phosphatidylserine decarboxylase, and two others are homologous to two of the three genes of the gerA and gerB loci (spore germination) from Bacillus subtilis. These are the first spore germination gene sequences obtained from a bacterium of the genus Clostridium.
Meyer
J
J
CEA Département de Biologie Moléculaire et structurale, CENG, Grenoble, France.