Ferric iron reductases and their contribution to unicellular ferrous iron uptake

Cain, Timothy J.; Smith, Aaron T.

doi:10.1016/j.jinorgbio.2021.111407

Cited by 37 publications

(19 citation statements)

References 86 publications

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“…In the bacterial cytoplasm, ferrisiderophore reduction involves the superfamily of siderophore-interacting proteins (SIP) composed of two distinct families: FSR family and SIP family ( Cain and Smith, 2021 ). The best understood FSR is E. coli FhuF, which uses a [2Fe-2S] cluster and catalyzes reduction of iron in the ferrisiderophore (desferrichrome and ferrioxamine) ( Matzanke et al, 2004 ).…”

Section: Siderophore Transportmentioning

confidence: 99%

Recent Advances in the Siderophore Biology of Shewanella

Liu

Wang

et al. 2022

Front. Microbiol.

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Despite the abundance of iron in nature, iron acquisition is a challenge for life in general because the element mostly exists in the extremely insoluble ferric (Fe3+) form in oxic environments. To overcome this, microbes have evolved multiple iron uptake strategies, a common one of which is through the secretion of siderophores, which are iron-chelating metabolites generated endogenously. Siderophore-mediated iron transport, a standby when default iron transport routes are abolished under iron rich conditions, is essential under iron starvation conditions. While there has been a wealth of knowledge about the molecular basis of siderophore synthesis, uptake and regulation in model bacteria, we still know surprisingly little about siderophore biology in diverse environmental microbes. Shewanella represent a group of γ-proteobacteria capable of respiring a variety of organic and inorganic substrates, including iron ores. This respiratory process relies on a large number of iron proteins, c-type cytochromes in particular. Thus, iron plays an essential and special role in physiology of Shewanella. In addition, these bacteria use a single siderophore biosynthetic system to produce an array of macrocyclic dihydroxamate siderophores, some of which show particular biological activities. In this review, we first outline current understanding of siderophore synthesis, uptake and regulation in model bacteria, and subsequently discuss the siderophore biology in Shewanella.

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Section: Siderophore Transportmentioning

confidence: 99%

Recent Advances in the Siderophore Biology of Shewanella

Liu

Wang

et al. 2022

Front. Microbiol.

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“…These molecules have a high affinity for Fe 3+ (K aff ≥ 10 30 M -1 ) and allow bacteria to compete against host Fe 3+ -binding proteins for ferric iron (8,10,11). Once acquired and delivered into the cytoplasm, Fe 3+ can be released by degrading the siderophore or through reducing Fe 3+ to Fe 2+ , which is accomplished by ferric iron reductases (8,(10)(11)(12). It is also well known that bacteria employ dedicated transport systems to acquire heme.…”

Section: Introductionmentioning

confidence: 99%

Biochemical and structural characterization of the fused Bacteroides fragilis NFeoAB domain reveals a role for FeoA

Sestok

Brown

Juliet

et al. 2021

Preprint

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Iron is an essential element for nearly all organisms, and under anoxic and/or reducing conditions, Fe2+ is the dominant form of iron available to bacteria. The ferrous iron transport (Feo) system has been identified as the primary prokaryotic Fe2+ import machinery, and two proteins (FeoA and FeoB) are conserved across most bacterial species. However, how FeoA and FeoB function relative to one another remained enigmatic. In this work we explored the distribution of feoAB operons predicted to encode for a fusion of FeoA tethered to the soluble N-terminal, G-protein domain of FeoB via a connecting linker region. We hypothesized that this fusion might poise FeoA to interact with FeoB in order to affect function. To test this hypothesis, we cloned, expressed, purified, and biochemically characterized the soluble NFeoAB fusion protein from Bacteroides fragilis, a commensal organism implicated in drug-resistant peritoneal infections. Using X-ray crystallography, we determined to 1.50 Å resolution the structure of BfFeoA, which adopts an SH3-like fold implicated in protein-protein interactions. In combination with structural modeling, small-angle X-ray scattering, and hydrogen-deuterium exchange mass spectrometry, we show that FeoA and NFeoB indeed interact in a nucleotide-dependent manner, and we have mapped the protein-protein interaction interface. Finally, using GTP hydrolysis assays, we demonstrate that BfNFeoAB exhibits one of the slowest known rates of Feo-mediated GTP hydrolysis and is not potassium-stimulated, indicating that FeoA-NFeoB interactions may function to stabilize the GTP-bound form of FeoB. Our work thus reveals a role for FeoA function in the fused FeoAB systems and suggests a broader role for FeoA function amongst prokaryotes.

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“…We then compared our homology models of Bf NFeoAB to structurally characterized Feo proteins to determine the locations of each domain of Bf NFeoAB. As our newly determined FeoA structure was not part of the homology modeling, we first superposed the FeoA portion of our Robetta model ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 ,…”

Section: Resultsmentioning

confidence: 99%

“…These molecules have a high affinity for Fe 3+ (K aff ≥ 10 30 M −1 ) and allow bacteria to compete against host Fe 3+ -binding proteins for ferric iron ( 8 , 10 , 11 ). Once acquired and delivered into the cytoplasm, Fe 3+ can be released by degrading the siderophore or through reducing Fe 3+ to Fe 2+ , which is accomplished by ferric iron reductases ( 8 , 10 , 11 , 12 ). It is also well known that bacteria use dedicated transport systems to acquire heme.…”

mentioning

confidence: 99%