Structure of vulnibactin, a new polyamine-containing siderophore from Vibrio vulnificus

Okujo, Noriyuki; Saito, Miki; Yamamoto, Satoshi; Yoshida, Takashi; Miyoshi, Shin‐ichi; Shinoda, Sumió

doi:10.1007/bf00140480

Cited by 94 publications

(78 citation statements)

References 30 publications

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“…This mechanism could be important for the non-epidemic V. cholerae that faces higher concentrations of siderocalin in blood while causing wounds, ear infections, or septicemia (9,10). Vibrio vulnificus, which can cause lethal septicemia and wound infection in humans, produces vulnibactin, a siderophore with a structure similar to that of vibriobactin (37). Therefore, we can reasonably expect that V. vulnificus may employ a similar mechanism to evade siderocalin (supplemental Fig.…”

Section: Resultsmentioning

confidence: 99%

Unique Iron Coordination in Iron-chelating Molecule Vibriobactin Helps Vibrio cholerae Evade Mammalian Siderocalin-mediated Immune Response

Zhang

et al. 2012

Journal of Biological Chemistry

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Background: Vibrio cholerae uses vibriobactin to sequester iron. The structure of ferric vibriobactin is controversial. Results: The three catechol moieties donate five, rather than six, oxygen atoms as iron ligands. Conclusion: Ferric vibriobactin can evade the human immune protein siderocalin in vitro because of the special iron coordination. Significance: The unique iron coordination could be used by pathogenic bacteria to evade the mammalian innate immune system of siderocalin.

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Section: Resultsmentioning

confidence: 99%

Unique Iron Coordination in Iron-chelating Molecule Vibriobactin Helps Vibrio cholerae Evade Mammalian Siderocalin-mediated Immune Response

Zhang

et al. 2012

Journal of Biological Chemistry

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“…1). This reaction is the committed step in the biosynthesis of salicylate-based siderophores in several pathogenic bacteria (1)(2)(3)(4)(5)(6). In plants, salicylate produced from isochorismate is important for the plant defense mechanisms known as local and systemic acquired resistance (7,8).…”

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Mechanistic Insights into the Isochorismate Pyruvate Lyase Activity of the Catalytically Promiscuous PchB from Combinatorial Mutagenesis and Selection

Künzler

Sasso

Gamper

et al. 2005

Journal of Biological Chemistry

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PchB from Pseudomonas aeruginosa possesses isochorismate pyruvate lyase (IPL) and weak chorismate mutase (CM) activity. Homology modeling based on a structurally characterized CM, coupled with randomization of presumed key active site residues (Arg 54 , Glu 90 , Gln 91 ) and in vivo selection for CM activity, was used to derive mechanistic insights into the IPL activity of PchB. Mutation of Arg 54 was incompatible with viability, and the CM and IPL activities of an engineered R54K variant were reduced 1,000-fold each. The observation that position 90 was tolerant to substitution but position 91 was essentially confined to Gln or Glu in functional variants rules out involvement of Glu 90 in general base catalysis. Counter to the generally accepted mechanistic hypothesis for pyruvate lyases, we propose for PchB a rare [1,5]-sigmatropic reaction mechanism that invokes electrostatic catalysis in analogy to the [3,3]-pericyclic rearrangement of chorismate in CMs. A common catalytic principle for both PchB functions is also supported by the covariance of the catalytic parameters for the CM and IPL activities and the shared functional requirement for a protonated Glu 91 in Q91E variants. The experiments demonstrate that focusing directed evolution strategies on the readily accessible surrogate activity of an enzyme can provide valuable insights into the mechanism of the primary reaction.Isochorismate pyruvate lyase (IPL) 2 catalyzes the conversion of isochorismate to salicylate and pyruvate (Fig. 1). This reaction is the committed step in the biosynthesis of salicylate-based siderophores in several pathogenic bacteria (1-6). In plants, salicylate produced from isochorismate is important for the plant defense mechanisms known as local and systemic acquired resistance (7,8). The catalytic mechanism of the IPL transformation is unknown, but it is formally related to the elimination of pyruvate from other shikimic acid metabolites, including chorismate, 2-amino-2-deoxyisochorismate, and 4-amino-4-deoxychorismate, catalyzed by chorismate lyase, anthranilate synthase, and 4-amino-4-deoxychorismate lyase, respectively (9). It has been proposed that proton abstraction by an enzymic general base initiates pyruvate elimination and aromatization in all of these pyruvate lyases (9 -12).The best characterized IPL is PchB from the opportunistic human pathogen Pseudomonas aeruginosa (13). Its gene pchB is part of an operon for the biosynthesis of the siderophore pyochelin (4,14,15). The sequence of PchB is unrelated to the pyruvate lyases mentioned above but instead resembles well characterized chorismate mutases (CMs) of the AroQ class (16,17), which catalyze the [3,3]-sigmatropic Claisen rearrangement of chorismate to prephenate (Fig. 1). PchB has the typical length of an AroQ domain with 20% overall sequence identity. Secondary structure prediction indicated that PchB has the same arrangement of ␣-helices as in EcCM (13), the CM domain (AroQ p ) of the bifunctional Escherichia coli chorismate mutase-prephenate dehydratase, for w...

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“…However, present study clearly indicated that expression of the iron-assimilating system resulting in sufficient bacterial growth was triggered in human serum if the iron chelator is absent. V. vulnificus biotype 1 synthesizes a phenolate-type siderophore named vulnibactin [30], which can sequester transferrin-bound iron for growth in human serum. Biosca et al [31] have reported that a siderophore produced by biotype 8 2 was a hydoxamate-type, not a phenolate-type.…”

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High growing ability of Vibrio vulnificus biotype 1 is essential for production of a toxic metalloprotease causing systemic diseases in humans

Watanabe

Miyoshi

Kawase

et al. 2004

Microbial Pathogenesis

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Vibrio vulnificus biotype 1, a causative agent of fatal septicemia or wound infection in humans, is known to produce a toxic metalloprotease as an important virulence determinant. V. vulnificus biotype 2 (serovar E), a primary eel pathogen, was found to elaborate an extracellular metalloprotease that was indistinguishable from that of biotype 1. The potential of V. vulnificus biotype 1 for production of the metalloprotease was compared with biotype 2 and other human non-pathogenic Vibrio species (V. anguillarum and V. proteolyticus). When cultivated at 25o C in tryptone-yeast extract broth supplemented with 0.9 % NaCl, all bacteria multiplied sufficiently and secreted significant amounts of the metalloprotease. However, at 37 o C with 0.9 % NaCl, V.anguillarum neither grew nor produced the metalloprotease. In human serum, only V.vulnificus biotype 1 revealed a steady multiplication accompanied with production of the extracellular metalloprotease. This prominent ability of biotype 1 in growth and protease production may contribute to cause serious systemic diseases in humans.

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Structure of vulnibactin, a new polyamine-containing siderophore from Vibrio vulnificus

Cited by 94 publications

References 30 publications

Unique Iron Coordination in Iron-chelating Molecule Vibriobactin Helps Vibrio cholerae Evade Mammalian Siderocalin-mediated Immune Response

Unique Iron Coordination in Iron-chelating Molecule Vibriobactin Helps Vibrio cholerae Evade Mammalian Siderocalin-mediated Immune Response

Mechanistic Insights into the Isochorismate Pyruvate Lyase Activity of the Catalytically Promiscuous PchB from Combinatorial Mutagenesis and Selection

High growing ability of Vibrio vulnificus biotype 1 is essential for production of a toxic metalloprotease causing systemic diseases in humans

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