Alr0397 Is an Outer Membrane Transporter for the Siderophore Schizokinen in<i>Anabaena</i>sp. Strain PCC 7120

Nicolaisen, Kerstin; Moslavac, Sunčana; Samborski, Anastazia; Valdebenito, Marianne; Hantke, Klaus; Maldener, Iris; Muro‐Pastor, Alicia M.; Flores, Enrique; Schleiff, Enrico

doi:10.1128/jb.01062-08

Cited by 78 publications

(99 citation statements)

References 55 publications

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“…PCC 7120 was extended as compared to current database entries for this organism (Cumino et al, 2007;Marcozzi et al, 2009;Du et al, 2013). The reconstruction also includes a proposed pathway for the iron (III)-siderophore schizokinen based on the biosynthesis route of a similar siderophore, rhizobactin, from Sinorhizobium meliloti 1021 (Lynch et al, 2001;Nicolaisen et al, 2008;D. Malatinszky and P.R.…”

Section: Resultsmentioning

confidence: 99%

A Comprehensively Curated Genome-Scale Two-Cell Model for the Heterocystous Cyanobacterium Anabaena sp. PCC 7120

2016

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ORCID IDs: 0000-0002-4155-2085 (D.M.); 0000-0001-7618-8204 (P.R.J.).Anabaena sp. PCC 7120 is a nitrogen-fixing filamentous cyanobacterium. Under nitrogen-limiting conditions, a fraction of the vegetative cells in each filament terminally differentiate to nongrowing heterocysts. Heterocysts are metabolically and structurally specialized to enable O 2 -sensitive nitrogen fixation. The functionality of the filament, as an association of vegetative cells and heterocysts, is postulated to depend on metabolic exchange of electrons, carbon, and fixed nitrogen. In this study, we compile and evaluate a comprehensive curated stoichiometric model of this two-cell system, with the objective function based on the growth of the filament under diazotrophic conditions. The predicted growth rate under nitrogen-replete and -deplete conditions, as well as the effect of external carbon and nitrogen sources, was thereafter verified. Furthermore, the model was utilized to comprehensively evaluate the optimality of putative metabolic exchange reactions between heterocysts and vegetative cells. The model suggested that optimal growth requires at least four exchange metabolites. Several combinations of exchange metabolites resulted in predicted growth rates that are higher than growth rates achieved by only considering exchange of metabolites previously suggested in the literature. The curated model of the metabolic network of Anabaena sp. PCC 7120 enhances our ability to understand the metabolic organization of multicellular cyanobacteria and provides a platform for further study and engineering of their metabolism.

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Section: Resultsmentioning

confidence: 99%

A Comprehensively Curated Genome-Scale Two-Cell Model for the Heterocystous Cyanobacterium Anabaena sp. PCC 7120

2016

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“…From the remaining eight proteins, which do not cluster with any known protein, only All0391 was previously identified as part of the putative schizokinen synthesis cluster (51).…”

Section: Table 3 Kinetic Parameters Determined In This Studymentioning

confidence: 99%

The TolC-like Protein HgdD of the Cyanobacterium Anabaena sp. PCC 7120 Is Involved in Secondary Metabolite Export and Antibiotic Resistance

Hahn

Stevanovic

Mirus

et al. 2012

Journal of Biological Chemistry

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Background:The metabolite and antibiotic export system of cyanobacteria is largely unexplored. Results: Uptake of ethidium bromid by Anabaena sp. depends on porin-type activity while its seceretion relies on HgdD. Conclusion:The antibiotic export of cyanobacteria involves a proton gradient-driven TolC activity and MFS-type proteins. Significance: TolC of Anabaena sp. is placed in the context of antibiotic uptake and export.

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“…Iron contents were measured according to Nicolaisen et al (2008). Briefly, the cells were collected and washed three times in 20 mM EDTA, then dried and digested for element determination by an atomic absorption spectrometer (AA240FS, Varian, Palo Alto, CA, USA).…”

Section: Construction Of Mutants Complementation and Overexpression mentioning

confidence: 99%

New insights into iron acquisition by cyanobacteria: an essential role for ExbB-ExbD complex in inorganic iron uptake

Jiang

Lou

et al. 2014

The ISME Journal

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Cyanobacteria are globally important primary producers that have an exceptionally large iron requirement for photosynthesis. In many aquatic ecosystems, the levels of dissolved iron are so low and some of the chemical species so unreactive that growth of cyanobacteria is impaired. Pathways of iron uptake through cyanobacterial membranes are now being elucidated, but the molecular details are still largely unknown. Here we report that the non-siderophore-producing cyanobacterium Synechocystis sp. PCC 6803 contains three exbB-exbD gene clusters that are obligatorily required for growth and are involved in iron acquisition. The three exbB-exbDs are redundant, but single and double mutants have reduced rates of iron uptake compared with wild-type cells, and the triple mutant appeared to be lethal. Short-term measurements in chemically well-defined medium show that iron uptake by Synechocystis depends on inorganic iron (Fe 0 ) concentration and ExbB-ExbD complexes are essentially required for the Fe 0 transport process. Although transport of iron bound to a model siderophore, ferrioxamine B, is also reduced in the exbB-exbD mutants, the rate of uptake at similar total [Fe] is about 800-fold slower than Fe 0 , suggesting that hydroxamate siderophore iron uptake may be less ecologically relevant than free iron. These results provide the first evidence that ExbB-ExbD is involved in inorganic iron uptake and is an essential part of the iron acquisition pathway in cyanobacteria. The involvement of an ExbB-ExbD system for inorganic iron uptake may allow cyanobacteria to more tightly maintain iron homeostasis, particularly in variable environments where iron concentrations range from limiting to sufficient.

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Alr0397 Is an Outer Membrane Transporter for the Siderophore Schizokinen inAnabaenasp. Strain PCC 7120

Cited by 78 publications

References 55 publications

A Comprehensively Curated Genome-Scale Two-Cell Model for the Heterocystous Cyanobacterium Anabaena sp. PCC 7120

A Comprehensively Curated Genome-Scale Two-Cell Model for the Heterocystous Cyanobacterium Anabaena sp. PCC 7120

The TolC-like Protein HgdD of the Cyanobacterium Anabaena sp. PCC 7120 Is Involved in Secondary Metabolite Export and Antibiotic Resistance

New insights into iron acquisition by cyanobacteria: an essential role for ExbB-ExbD complex in inorganic iron uptake

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