Iron acquisition in plague: modular logic in enzymatic biogenesis of yersiniabactin by Yersinia pestis

Gehring, Amy M.; DeMoll, Edward; Fetherston, Jacqueline D.; Mori, Ichiro; Mayhew, George F.; Blattner, Frederick R.; Walsh, Christopher T.; Perry, Robert D.

doi:10.1016/s1074-5521(98)90115-6

Cited by 227 publications

(322 citation statements)

References 47 publications

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“…6) and are slightly smaller proteins than PchA, might carry out the direct conversion of chorismate to salicylate, basically because in these organisms no pchB homolog has been found in the vicinity of the ICS genes (43,44). We have examined the purified P. aeruginosa ICS for its ability to produce salicylate but found no evidence for such a reaction in vitro (Fig.…”

Section: Discussionmentioning

confidence: 99%

Isochorismate Synthase (PchA), the First and Rate-limiting Enzyme in Salicylate Biosynthesis of Pseudomonas aeruginosa

Gaille

Reimmann

Haas

2003

Journal of Biological Chemistry

103

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In Pseudomonas aeruginosa the extracellular metabolite and siderophore pyochelin is synthesized from two major precursors, chorismate and L-cysteine via salicylate as an intermediate. The regulatory role of isochorismate synthase, the first enzyme in the pyochelin biosynthetic pathway, was studied. This enzyme is encoded by pchA, the last gene in the pchDCBA operon. The PchA protein was purified to apparent electrophoretic homogeneity from a PchA-overexpressing P. aeruginosa strain. The native enzyme was a 52-kDa monomer in solution, and its activity strictly depended on Mg 2؉ . At pH 7.0, the optimum, a K m ‫؍‬ 4.5 M and a k cat ‫؍‬ 43.1 min ؊1 were determined for chorismate. No feedback inhibitors or other allosteric effectors were found. The intracellular PchA concentration critically determined the rate of salicylate formation both in vitro and in vivo. In cultures grown in iron-limiting media to high cell densities, overexpression of the pchA gene resulted in overproduction of salicylate as well as in enhanced pyochelin formation. From this work and earlier studies, it is proposed that one important factor influencing the flux through the pyochelin biosynthetic pathway is the PchA concentration, which is determined at a transcriptional level, with pyochelin acting as a positive signal and iron as a negative signal.

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Section: Discussionmentioning

confidence: 99%

Isochorismate Synthase (PchA), the First and Rate-limiting Enzyme in Salicylate Biosynthesis of Pseudomonas aeruginosa

Gaille

Reimmann

Haas

2003

Journal of Biological Chemistry

103

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“…YbtX shows homology to AmpG, which is proposed to act as a signal transducer or permease in the β-lactamase induction system (Lindquist et al, 1993). The function of YbtX and its role in virulence are still unknown Gehring et al, 1998). A similar operon (irp6, irp7, irp8 and irp9) has been described for Y. enterocolitica with 98-99 % homology to the corresponding sequences of Y. pestis (Rakin et al, 1999a).…”

Section: Introductionmentioning

confidence: 99%

Functional analysis of yersiniabactin transport genes of Yersinia enterocolitica

et al. 2001

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. These results suggest that besides irp6, irp7 and fyuA, additional genes are required for sufficient Fe-Ybt transport/utilization. Finally, it was shown that irp6, irp7 and fyuA but not irp8 are involved in controlling Ybt biosynthesis and fyuA gene expression : irp6 and/or irp7 mutation leads to upregulation whereas fyuA mutation leads to downregulation. However, fyuAdependent control of Ybt biosynthesis could be bypassed in a fyuA mutant by ingredients of chrome azurol S (CAS) siderophore indicator agar.

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“…The biosynthetic genes for Ybt include ybtE, encoding the one-domain 67-kDa YbtE, and irp1 and irp2, encoding two high molecular weight proteins, HMWP1 and HMWP2, respectively ( Fig. 1 A) (6). HMWP2 and HMWP1 form an assembly line of 16 predicted domains to convert salicylate, three cysteines, malonyl-CoA, and three adenosylmethionines to the mixed nonribosomal peptide͞polyketide Ybt (Fig.…”

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confidence: 99%

“…HMWP1 is predicted to be a hybrid of a five-domain polyketide synthase (PKS) (ketoacyl synthase, acyltransferase, methyltransferase 2, ketoacyl reductase, acyl carrier protein: KS-AT-MT 2 -KR-ACP) and a fourdomain NRPS (cyclization domain 3, methyltransferase 3, peptidyl carrier protein 3, thioesterase: Cy 3 -MT 3 -PCP 3 -TE) ( Fig. 1 A) (6). The PKS module of HMWP1 probably synthesizes the t-butyl linker, whereas the NRPS module assembles the third fivemembered heterocycle of Ybt (6).…”

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confidence: 99%

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Acyl-CoA hydrolysis by the high molecular weight protein 1 subunit of yersiniabactin synthetase: Mutational evidence for a cascade of four acyl-enzyme intermediates during hydrolytic editing

Suo

Chen²,

Walsh³

2000

Proc. Natl. Acad. Sci. U.S.A.

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Yersiniabactin (Ybt) synthetase is a three-subunit, 17-domain [7 domains in high molecular weight protein (HMWP)2, 9 in HMWP1, and 1 in YbtE] enzyme producing the virulence-conferring siderophore yersiniabactin in Yersinia pestis. The 350-kDa HMWP1 subunit contains a polyketide synthase module (KS-AT-MT 2-KR-ACP) and a nonribosomal peptide synthetase module (Cy3-MT3-PCP3-TE). The fulllength HMWP1 was heterologously overexpressed in Escherichia coli and purified to near homogeneity. The purified HMWP1 showed thioesterase activity toward acyl-CoAs, such as acetyl-CoA, benzoylCoA, and malonyl-CoA, with saturation kinetics and relative catalytic efficiencies of 172:50:1. A chain-releasing thioesterase (TE) activity is ascribed to the C-terminal TE domain, and this was substantiated by the fact that acyl-N-acetylcysteamines were hydrolyzed by the didomain PCP 3-TE fragment of HMWP1. However, PCP3-TE failed to hydrolyze any of the acyl-CoAs, suggesting the TE domain does not recognize CoA moiety, thus the acyl-CoA hydrolysis by HMWP1 must involve other domains. Ser-to-Ala mutants in each of the AT, ACP, PCP 3, and TE domains reduced hydrolysis rates of the two fastest substrates, acetyl-CoA and benzoyl-CoA, by more than two orders of magnitude. Thus, the acyl-CoA hydrolysis activity requires 4 of the 9 domains of HMWP1, and it is consistent with autoacylation of the AT domain active site serine and subsequent passage of the itinerant acyl chain from AT to ACP to PCP 3 to the TE domain, a cascade of four sequential acyl-enzyme intermediates, for hydrolytic turnover. This could represent an editing pathway for this polyketide synthase͞nonribosomal peptide synthetase assembly line.

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Iron acquisition in plague: modular logic in enzymatic biogenesis of yersiniabactin by Yersinia pestis

Cited by 227 publications

References 47 publications

Isochorismate Synthase (PchA), the First and Rate-limiting Enzyme in Salicylate Biosynthesis of Pseudomonas aeruginosa

Isochorismate Synthase (PchA), the First and Rate-limiting Enzyme in Salicylate Biosynthesis of Pseudomonas aeruginosa

Functional analysis of yersiniabactin transport genes of Yersinia enterocolitica

Acyl-CoA hydrolysis by the high molecular weight protein 1 subunit of yersiniabactin synthetase: Mutational evidence for a cascade of four acyl-enzyme intermediates during hydrolytic editing

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