Loihichelins A−F, a Suite of Amphiphilic Siderophores Produced by the Marine Bacterium <i>Halomonas</i> LOB-5

Homann, Vanessa V.; Sandy, Moriah; Tincu, J. Andy; Templeton, Alexis S.; Tebo, Bradley M.; Butler, Alison

doi:10.1021/np800640h

Cited by 91 publications

(103 citation statements)

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“…Often, they are amphiphilic compounds that contain a fatty acid tail linked to a peptidic head group. These compounds include the marinobactins, amphibactins, moanachelins, aquachelins, loihichelins, all of which bind Fe with three hydroxamate groups [Kanoh et al, 2003;Holt et al, 2005;Homann et al, 2009a;Zhang et al, 2009;. Other marine amphiphilic siderophores include synechobactins and ochrobactins, which are mixed-mode compounds containing both citrate and two hydroxamate groups .…”

Section: Sources and Classes Of Iron Ligandsmentioning

confidence: 99%

Molecular determination of marine iron ligands by mass spectrometry

Boiteau¹

2016

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Abstract:Marine microbes produce a wide variety of metal binding organic ligands that regulate the solubility and availability of biologically important metals such as iron, copper, cobalt, and zinc.In marine environments where the availability of iron limits microbial growth and carbon fixation rates, the ability to access organically bound iron confers a competitive advantage. Thus, the compounds that microbes produced to acquire iron play an important role in biogeochemical carbon and metal cycling. However, the source, abundance, and identity of these compounds are poorly understood. To investigate these processes, sensitive methodologies were developed to gain a compound-specific window into marine iron speciation by combining trace metal clean sample collection and chromatography with inductively coupled plasma mass spectrometry (LC-ICPMS) and electrospray ionization mass spectrometry (LC-ESIMS). Coupled with isotope pattern assisted search algorithms, these tools provide a means to quantify and isolate specific iron binding ligands from seawater and marine cultures, identify them based on their mass and fragmentation spectra, and investigate their metal binding kinetics.Using these techniques, we investigated the distribution and diversity of marine iron binding ligands. In cultures, LC-ICPMS-ESIMS was used to identify new members of siderophore classes produced by marine cyanobacteria and heterotrophic bacteria, including synechobactins and marinobactins. Applications to natural seawater samples from the Pacific Ocean revealed a wide diversity of both known and novel metal compounds that are linked to specific nutrient regimes. Ferrioxamines B, E, and G were identified in productive coastal waters near California and Peru, in oligotrophic waters of the North and South Pacific Gyre, and in association with zooplankton grazers. Siderophore concentrations were up to five-fold higher in iron-deficient offshore waters (9pM) and were dominated by amphibactins, amphiphilic siderophores that partition into cell membranes. Furthermore, synechobactins were detected within nepheloid layers along the continental shelf. These siderophores reflect adaptations that impact dissolved iron bioavailability and thus have important consequences for marine ecosystem community structures and primary productivity. The ability to map and characterize these compounds has opened new opportunities to better understand mechanisms that link metals with the microbes that use them. 4Acknowledgements:

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Section: Sources and Classes Of Iron Ligandsmentioning

confidence: 99%

Molecular determination of marine iron ligands by mass spectrometry

Boiteau¹

2016

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“…Acyl siderophores with longer peptidic headgroups, such as the loihichelins (8 amino acids) and aquachelins (7 amino acids) (Figure 1), are quite hydrophilic and are isolated from the supernatant of harvested cultures (Martinez et al 2000;Homann et al 2009). The marinobactins (Figure 1) produced by Marinobacter sp.…”

Section: Amphiphilic Siderophores From Marine Environmentsmentioning

confidence: 99%

“…Many structurally characterized amphiphilic siderophores also contain β-hydroxyaspartic acid residues, including the marinobactins, aquachelins, loihichelins, cupriachelin, taiwachelin and serobactins (Martinez et al 2000;Homann et al 2009;Rosconi et al 2013). The aquachelins produced by Halomonas aquamarina strain DS40M3 have a N-terminal β-hydroxyaspartic acid residue connected to the fatty acid.…”

Section: Photochemistry Of Amphiphilic Siderophoresmentioning

confidence: 99%

“…Many marine siderophores are distinguished by the presence of a fatty acid appendage connected to a peptidic or citrate-based headgroup resulting in an amphiphilic compound (Martinez et al 2000;Homann et al 2009;Martin et al 2006;Zane et al 2014). Amphiphilic siderophores are generally produced in a suite where the headgroup, which coordinates Fe(III) remains constant, but the fatty acid appendage ranges in length, degree of unsaturation and functionality.…”

Section: Introductionmentioning

confidence: 99%

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Acyl peptidic siderophores: structures, biosyntheses and post-assembly modifications

Kem

Butler

2015

Biometals

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Abstract:Acyl peptidic siderophores are produced by a variety of bacteria and possess unique amphiphilic properties.Amphiphilic siderophores are generally produced in a suite where the iron(III)-binding headgroup remains constant while the fatty acid appendage varies by length and functionality. Acyl peptidic siderophores are commonly synthesized by non-ribosomal peptide synthetases (NRPS); however, the method of peptide acylation during biosynthesis can vary between siderophores. Following biosynthesis, acyl siderophores can be further modified enzymatically to produce a more hydrophilic compound, which retains its ferric chelating abilities as demonstrated by pyoverdine from Pseudomonas aeruginosa and the marinobactins from certain Marinobacter species.Siderophore hydrophobicity can also be altered through photolysis of the ferric complex of certain β-hydroxyaspartic acid-containing acyl peptidic siderophores.

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“…The structure of these ligands is largely unknown, and changes in speciation caused by chemical perturbation of the redox state of these ligands may reveal important clues regarding their structure. Manganese may also be complexed by some marine siderophores Homann et al 2009), though the influence of complexation on manganese scavenging is still largely unknown. Speciation also likely influences the bioavailability of the metal to microorganisms.…”

Section: Cobalt Iron and Manganese Biogeochemistry In The Ocean: MImentioning

confidence: 99%

Influences on the oceanic biogeochemical cycling of the hybrid-type metals : cobalt, iron, and manganese

Noble¹

2012

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, in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the field of Chemical Oceanography Thesis AbstractTrace metal cycling is one of many processes that influence ocean ecosystem dynamics. Cobalt, iron, and manganese are redox active trace metal micronutrients with oceanic distributions that are influenced by both biological and abiotic sources and sinks. Their open ocean concentrations range from picomolar to nanomolar, and their bioavailabilities can impact primary production. Understanding the biogeochemical cycling of these hybrid-type metals with an emphasis on cobalt was the focus of this thesis. This was accomplished by determining the dissolved distributions of these metals in oceanic regions that were characterized by different dominant biogeochemistries.A large subsurface plume of dissolved cobalt, iron, and manganese was found in the Eastern South Atlantic. The cause of this plume is a combination of reductive dissolution in coastal sediments, wind-driven upwelling, advection, biological uptake, and remineralization. Additional processes that are discussed as sources of metals to the regions studied during this thesis include isopycnal uplift within cold-core eddies (Hawaii), ice melt (McMurdo Sound, Antarctica), riverine input (Arctic Ocean), and winter mixing (McMurdo Sound). The biological influence on surface ocean distributions of cobalt was apparent by the observation of linear relationships between cobalt and phosphate in mid to low latitudes. The cobalt:phosphate ratios derived from these correlations changed over orders of magnitude, revealing dynamic variability in the utilization, demand, and sources of this micronutrient. Speciation studies suggest that there may be two classes of cobalt binding ligands, and that organic complexation plays an important role in preventing scavenging of cobalt in the ocean.These datasets provided a basis for comparing the biogeochemical cycles of cobalt, iron, and manganese in three oceanic regimes (Hawaii, South Atlantic, McMurdo Sound). The relative rates of scavenging for these metals show environmental variability: in the South Atlantic, cobalt, iron, and manganese were scavenged at very different rates, but in the Ross Sea, mixing and circulation over the shallow sea was fast, scavenging played a minor role, and the cycles of all three metals were coupled. Studying the distributions of these metals in biogeochemically distinct regions is a step toward a better understanding of their oceanic cycles.Thesis supervisor: Mak Saito Title: Associate Scientist 4 Acknowledgements I'd like to thank my advisor, Mak, for his support throughout my time in Woods Hole, for getting me to try my hand at jamming, for torturing me with his deadpan deliveries, for teaching me the paranoia that accompanies trace metal clean techniques, for introducing me to sukiyaki, for his understanding and flexibility, for somehow making me laugh whenever I think the world is ending, for having faith in me when I didn't, and lastly for the freedom I was ...

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Loihichelins A−F, a Suite of Amphiphilic Siderophores Produced by the Marine Bacterium Halomonas LOB-5

Cited by 91 publications

References 31 publications

Molecular determination of marine iron ligands by mass spectrometry

Molecular determination of marine iron ligands by mass spectrometry

Acyl peptidic siderophores: structures, biosyntheses and post-assembly modifications

Influences on the oceanic biogeochemical cycling of the hybrid-type metals : cobalt, iron, and manganese

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