Rhodospirillum rubrum mutant

An Fe-only nitrogenase has also been isolated from a nifH mutant of Rhodospirillum rubrum and was characterized as an a2/82<% hex-amer containing only iron, no molybdenum or vanadium, with an o 2Fe4S4-containing Fe protein. A factor could be extracted from the FeFe protein into NMF that combined with apo-MoFe protein to form an active enzyme 193). 

M. Kern, W. Klipp, J. H. Klemme (1994) Increased nitrogenase-dependent H2 photoproduction by hup mutants of Rhodospirillum rubrum, Appl. Environmental Microbo., 60 1768-1774... 

The molybdenum cofactor from Rhodospirillum rubrum is dialyzable and is insensitive to trypsin (9). The cofactor can easily be inactivated by heat. One of the problems in purifying this cofactor is the instability and low yields from purified enzymes and crude extracts. Lee et al. (10) showed that the molybdenum cofactor is stabilized by 0.01M sodium molybdate and that the absence of air adds to the stability. These workers used Mo" labeling to show that the molybdenum from the cofactor is found in activated nitrate reductase from the mutant strain of N. crassa. 

Rhodospirillum rubrum G9, a carotenoidless mutant, was grown photosynthetically at 32 Cells were harvested in... 

Rivas, E.A., N.L. Kerber, A.A. Viale, and A.F. Garcia Isolation of a Basic Membrane Fraction Enriched in an Ornithine-Containing Lipid, from a Blue-green Mutant of Rhodospirillum rubrum. FEBS-Letters 11, 37 (1970). 

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