Alteration of the Fe protein of nitrogenase by oxygen in the cyanobacterium Anabaena sp. strain CA

Smith, Russell L.; Baalen, Chase Van; Tabita, F. Robert

doi:10.1128/jb.169.6.2537-2542.1987

Cited by 57 publications

(43 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…One hundred percent activity represents 18 nmol CzH4 formed min-l (mg protein)-'. noted in other cyanobacteria (Ernst et al, 1990;Reich & Boger, 1989;Smith et al, 1987;Stal & Bergman, 1990).…”

Section: Derepression Of Nitrogenasementioning

confidence: 99%

Nitrogenase derepresssion, its regulation and metabolic changes associated with diazotrophy in the non-heterocystous cyanobacterium Plectonema boryanum PCC 73110

N.¹,

Borthakur²,

Bergman³

1992

Journal of General Microbiology

View full text Add to dashboard Cite

The regulation of nitrogenase derepression, plus the catalytic activity and protein concentration of glutamine synthetase (GS), nitrate reductase (NR), ribulose-l$-bisphosphate carbxylase/oxygenase (Rubisco) and phycoerythrin (PE) were studied in the filamentous non-heterocystous cyanobacterium PIectonemu boryanum PCC 73110. Both nitrogen limitation and microaerobic incubation were essential for the derepression of nitrogenase. Oxygen caused irreversible inactivation of nitrogenase, as well as repression of its synthesis. A temporal separation of N2 fixation and net photosynthetic O2 evolution was observed under a N2/C02 ( 9 5 5 , v/v) atmosphere. Repeated peaks of nitrogenase and growth were observed. Immunogold localization showed that in N2-fixing cultures, all cells, including those undergoing division, contained nitrogenase, and that the nitrogenase antigen was uniformly distributed throughout the cells without any preferential association with cellular structures. Rubisco was mainly located in carboxysomes of both N2-fixing and NOT-grown cells. Both N2-fixing and NOTgrown cells showed similar levels of PE, which was associated with the thylakoid membranes. GS antigen was distributed throughout the cells and the relative amounts of this enzyme, as well as its activity, were 20% higher in N2-fixing than in NOT-grown cultures. NO, uptake and NR systems were found to be NOT-inducible, with very low activities in N2-fixing cultures. The latter may be important in avoiding competition for Mo between nitrogenase and NR.

show abstract

Section: Derepression Of Nitrogenasementioning

confidence: 99%

Nitrogenase derepresssion, its regulation and metabolic changes associated with diazotrophy in the non-heterocystous cyanobacterium Plectonema boryanum PCC 73110

N.¹,

Borthakur²,

Bergman³

1992

Journal of General Microbiology

View full text Add to dashboard Cite

show abstract

“…Under conditions of N limitation, some vegetative cells of Anabaena oscillarioides (a filamentous freshwater cyanobacterium) differentiate to form heterocysts non-growing, specialized cells in which N 2 is fixed into organic N (Stewart, 1973;Herrero et al, 1979;Kumar et al, 1983;Wolk, 1996Wolk, , 2000Meeks and Elhai, 2002). Because the enzyme that catalyzes N 2 fixation, nitrogenase, is inhibited by oxygen (Stewart, 1973;Gotto et al, 1979;Smith et al, 1987), heterocysts must be physically isolated from nearby vegetative cells, which are sites of oxygenic photosynthesis and CO 2 -fixation. This isolation, however, cannot be complete, as vegetative and heterocyst cells must exchange energy, organic C and fixed N (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Carbon and nitrogen fixation and metabolite exchange in and between individual cells of Anabaena oscillarioides

et al. 2007

View full text Add to dashboard Cite

Filamentous nitrogen fixing cyanobacteria are key players in global nutrient cycling, but the relationship between CO 2 -and N 2 -fixation and intercellular exchange of these elements remains poorly understood in many genera. Using high-resolution nanometer-scale secondary ion mass spectrometry (NanoSIMS) in conjunction with enriched H 13 CO 3 À and 15 N 2 incubations of Anabaena oscillarioides, we imaged the cellular distributions of C, N and P and 13 C and 15 N enrichments at multiple time points during a diurnal cycle as proxies for C and N assimilation. The temporal and spatial distributions of the newly fixed C and N were highly heterogeneous at both the intra-and inter-cellular scale, and indicative of regions performing active assimilation and biosynthesis. Subcellular components such as the neck region of heterocycts, cell division septae and putative cyanophycin granules were clearly identifiable by their elemental composition. Newly fixed nitrogen was rapidly exported from heterocysts and was evenly allocated among vegetative cells, with the exception of the most remote vegetative cells between heterocysts, which were N limited based on lower 15 N enrichment. Preexisting functional heterocysts had the lowest levels of 13 C and 15 N enrichment, while heterocysts that were inferred to have differentiated during the experiment had higher levels of enrichment. This innovative approach, combining stable isotope labeling and NanoSIMS elemental and isotopic imaging, allows characterization of cellular development (division, heterocyst differentiation), changes in individual cell composition and cellular roles in metabolite exchange.

show abstract

“…Recently, it was noticed that addition of ammonia or an oxygen shock abolished nitrogenase activity in two Anabaena strains and that the dinitrogenase reductase (the Fe protein of nitrogenase) was modified (36,39). Fe protein modification as another means of activity control was first observed in Rhodospirillum rubrum (22,23,32).…”

mentioning

confidence: 99%

Modification of dinitrogenase reductase in the cyanobacterium Anabaena variabilis due to C starvation and ammonia

1990

View full text Add to dashboard Cite

In the heterocystous cyanobacterium Anabaena variabilis, a change in nitrogenase activity and concomitant modification of dinitrogenase reductase (the Fe protein of nitrogenase) was induced either by NH4Cl at pH 10 (S. Reich and P. Boger, FEMS Microbiol. Lett. 58:81-86, 1989) or by cessation of C supply resulting from darkness, CO2 limitation, or inhibition of photosystem II activity. Modification induced by both C limitation and NH4Cl was efficiently prevented by anaerobic conditions. Under air, endogenously stored glycogen and added fructose protected against modification triggered by C limitation but not by NH4Cl. With stored glycogen present, dark modification took place after inhibition of respiration by KCN. Reactivation of inactivated nitrogenase and concomitant demodification of dinitrogenase reductase occurred after restoration of diazotrophic growth conditions. In previously C-limited cultures, reactivation was also observed in the dark after addition of fructose (heterotrophic growth) and under anaerobiosis upon reillumination in the presence of a photosynthesis inhibitor. The results indicate that modification of dinitrogenase reductase develops as a result of decreased carbohydrate-supported reductant supply of the heterocysts caused by C limitation or by increased diversion of carbohydrates towards ammonia assimilation. Apparently, a product of N assimilation such as glutamine is not necessary for modification. The increase of oxygen concentration in the heterocysts is a plausible consequence of all treatments causing Fe protein modification.In the cyanobacterium Anabaena variabilis, aerobic nitrogen fixation by the enzyme complex nitrogenase (EC 1.18.6.1) is located in the heterocysts (12,13). Heterocysts are devoid of an oxygenic photosystem II and ribulose-1,5-bisphosphate carboxylase, which are operative in vegetative cells. Thus, N2 fixation is spatially separated from water photolysis and coupled ATP formation. The necessary ATP is generated in the heterocysts by photosystem Imediated photophosphorylation and by oxidative phosphorylation. Reductants are produced by dissimilation of fixed carbon imported from vegetative cells into heterocysts (for a review, see reference 41).It is accepted that cyanobacterial nitrogenase activity is controlled at the level of gene expression (13) and by the ability of cells to modulate the supply of reductants and ATP (7,8). Under air, nitrogenase activity in vivo is known to be inhibited by dark treatment (9, 33) and by photosynthesis inhibitors such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), which is considered to be due to reductant limitation of heterocysts and concurrent oxygen inactivation of the heterocystous nitrogenase enzyme complex (24, 25). The repressing effect of excess ammonia and other nitrogenous compounds was attributed to enzyme turnover and regulation of enzyme biosynthesis (see, for example, references 4, 13, and 33). Some authors interpreted these effects in terms of inhibition of nitrogenase activity, possibly exerted by glutami...

show abstract

Alteration of the Fe protein of nitrogenase by oxygen in the cyanobacterium Anabaena sp. strain CA

Cited by 57 publications

References 33 publications

Nitrogenase derepresssion, its regulation and metabolic changes associated with diazotrophy in the non-heterocystous cyanobacterium Plectonema boryanum PCC 73110

Nitrogenase derepresssion, its regulation and metabolic changes associated with diazotrophy in the non-heterocystous cyanobacterium Plectonema boryanum PCC 73110

Carbon and nitrogen fixation and metabolite exchange in and between individual cells of Anabaena oscillarioides

Modification of dinitrogenase reductase in the cyanobacterium Anabaena variabilis due to C starvation and ammonia

Contact Info

Product

Resources

About