ISSN:
1365-2958
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
,
Medicine
Notes:
A nifJ-like gene was identified in the photosynthetic purple non-sulphur bacterium Rhodospirillum rubrum. A DNA segment hybridizing to Klebsiella pneumoniae nifJ was isolated, the gene was inactivated, and a mutant strain, SNJ-1, was constructed by allele replacement. The mutation was confirmed by DNA sequencing, Northern blotting and by the lack of pyruvate oxidoreductase activity. This is the first report of a nifJ-like gene in photosynthetic bacteria. Unexpectedly, SNJ-1 was capable of nitrogen fixation, and growth was similar to the wild-type strain under all conditions investigated. Therefore, this is also the first demonstration that a nifJ homologue, when present, is not essential for nitrogen fixation in a diazotroph. The nifJ-like gene was sequenced and found to have considerable similarity to published nifJ gene sequences from other organisms. By primer extension, the initiation site for transcription was located, and a typical σ54 promoter sequence was identified.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-2958.1996.5311054.x
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