- Si-enterobactin from the endophytic Streptomyces sp. KT-S1-B5-a potential silicon transporter in Nature?
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Si-enterobactin (2a), a hexacoordinated complex of the siderophore enterobactin (2b) with silicon as the central atom, was isolated from an endophytic Streptomyces sp. occurring in Piper guinensis roots. The structure and absolute configuration were determined from NMR and MS data, and by X-ray diffraction. The orientation of the molecule along the pseudo-3-fold axis shows that the coordination environment of the silicon atom complexed with three bidentate ligands is Δ. We assume that 2a or related complexes may be involved in the transport of silicon in plants, diatoms, or other silicon-dependent organisms. The Royal Society of Chemistry.
- Kenla, Timothee J. N.,Tatong, Michel D. Kongue,Talontsi, Ferdinand Mouafo,Dittrich, Birger,Frauendorf, Holm,Laatsch, Hartmut
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- Total Synthesis of Enterobactin via an Organotin Template
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A novel synthesis of the natural iron carrier enterobactin, based on a single step conversion of the tritylated serine β-lactone (1) into the enterobactin skeleton (3) via the use of a cyclic organotin compound as a template, is described.
- Shanzer, Abraham,Libman, Jacqueline
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- Facile and Versatile Chemoenzymatic Synthesis of Enterobactin Analogues and Applications in Bacterial Detection
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Siderophores, such as enterobactin (Ent), are small molecules that can be selectively imported into bacteria along with iron by cognate transporters. Siderophore conjugates are thus a promising strategy for delivering functional reagents into bacteria. In this work, we present an easy-to-perform, one-pot chemoenzymatic synthesis of functionalized monoglucosylated enterobactin (MGE). When functionalized MGE is conjugated to a rhodamine fluorophore, which affords RhB-Glc-Ent, it can selectively label Gram-negative bacteria that utilize Ent, including some E. coli strains and P. aeruginosa. V. cholerae, a bacterium that utilizes linearized Ent, can also be weakly targeted. Moreover, the targeting is effective under iron-limiting but not iron-rich conditions. Our results suggest that the RhB-Glc-Ent probe is sensitive not only to the bacterial strain but also to the iron condition in the environment.
- Lee, Albert A.,Chen, Yi -Chen S.,Ekalestari, Elisa,Ho, Sheng -Yang,Hsu, Nai -Shu,Kuo, Tang -Feng,Wang, Tsung -Shing Andrew
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supporting information
p. 12338 - 12342
(2016/10/13)
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- Synthesis and structural characterization of hexacoordinate silicon, germanium, and titanium complexes of the E. coli siderophore enterobactin
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The E. coli siderophore enterobactin, one of the strongest FeIII chelators known to date, is also capable of binding SiIV under physiological conditions. We report on the synthesis and structural characterization of the tris(catecholate) SiIV-enterobactin complex and its GeIV and TiIV analogues. Comparative structural analysis, supported by quantum-chemical calculations, reveals the correlation between the ionic radius and the structural changes in enterobactin upon complexation. Copyright
- Baramov, Todor,Keijzer, Karlijn,Irran, Elisabeth,Moesker, Eva,Baik, Mu-Hyun,Suessmuth, Roderich
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supporting information
p. 10536 - 10542
(2013/08/23)
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- Structural change of the enterobactin synthetase in crowded solution and its relation to crowding-enhanced product specificity in nonribosomal enterobactin biosynthesis
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Significant conformational change is detected by circular dichroism and fluorimetry for the major component of the enterobactin synthetase in crowded solutions mimicking the intracellular environment. The structural change correlates well with the extent of the crowding-induced side product suppression in nonribosomal enterobactin synthesis. In contrast, protein-stabilizing solvophobic agents such as glycerol have no effect on the formation of side products, excluding crowding-induced protein stability as a cause for the observed enhancement of the product specificity of the synthetase. These results strongly support that macromolecular crowding is an indispensable physiological factor for normal functioning of the nonribosomal enterobactin synthetase by altering the active sites to increase its product specificity.
- Guo, Zu-Feng,Jiang, Ming,Zheng, Suilan,Guo, Zhihong
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body text
p. 3855 - 3858
(2010/09/03)
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- Oxinobactin, a siderophore analogue to enterobactin involving 8-hydroxyquinoline subunits: Synthesis and iron binding ability
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Oxinobactin, a siderophore analogue to enterobactin but possessing 8-hydroxyquinoline instead of catechol complexing subunits, has been synthesized starting from l-serine and 8-hydroxyquinoline. Comparative iron binding studies showed that oxinobactin is as effective as enterobactin for the complexation of FeIII at physiological pH but with improved complexing ability at acidic pH.
- du Moulinet d'Hardemare, Amaury,Alnaga, Nivine,Serratrice, Guy,Pierre, Jean-Louis
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scheme or table
p. 6476 - 6478
(2009/10/01)
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- Suppression of linear side products by macromolecular crowding in nonribosomal enterobactin biosynthesis
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Nonribosomal enterobactin synthetase of Escherichia coli was found to prematurely release a large amount of linear precursors in an in vitro reconstitution. However, these side products are suppressed to negligible levels by polymeric cosolvents that create macromolecular crowding, a prominent feature of the intracellular environment. These findings show that macromolecular crowding is essential to normal functioning of the nonribosomal peptide synthetase and suggest that it may be crucial to btotechnological utilization of similar enzyme systems.
- Guo, Zu-Feng,Jiang, Ming,Zheng, Suilan,Guo, Zhihong
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p. 649 - 652
(2008/09/16)
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- A much improved synthesis of the siderophore enterobactin
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Enterabadin, the cyclic trimer of N-(2,3-dihydroxybenzoyl)-L-serine has been efficiently prepared. A simple and high yield procedure has been developed for construction of N-protected serine trilactone as the key intermediate: methyl N-trityl-L-serinate and 2,2-dibutyl-1,3,2-dioxastannolane were refluxed in xylene to produce the triolide as the only lactone product in 85% yield.
- Ramirez, Robert J. A.,Karamanukyan, Levon,Ortiz, Steven,Gutierrez, Carlos G.
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p. 749 - 752
(2007/10/03)
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- Synthesis of Enterochelin
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Enterochelin (enterobactin), the cyclic trilactone of N-(2,3-dihydroxybenzoyl)-L-serine 6, an important enterobacterial iron-transporting compound, has been synthesised from N,N-dibenzyl-L-serine 2 in four steps.The protected amino acid was oligomerised using N,N-dicyclohexylcarbodiimide in a high-dilution procedure yielding a mixture of di-, tri- and tetra-lactones.The trilactone 3b was deprotected by hydrogenolysis and the resultant amine 4 was acylated with 2,3-dibenzyloxybenzoyl chloride to yield hexa-O-benzylenterochelin 5.This upon hydrogenolysis gave enterochelin in moderate yield.
- Rogers, Henry J.
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p. 3073 - 3076
(2007/10/03)
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