Structural and Biochemical Characterization of the Flavin-Dependent Siderophore-Interacting Protein from Acinetobacter baumannii
| Autor: | John J. Tanner, Justin A. Shapiro, Timothy A. Wencewicz, David A. Korasick, Hannah Valentino, Tabbetha J Bohac, Pablo Sobrado |
|---|---|
| Přispěvatelé: | Biochemistry |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Siderophore
biology Chemistry Stereochemistry General Chemical Engineering 0904 Chemical Engineering Virulence General Chemistry Flavin group biology.organism_classification Shewanella Article Acinetobacter baumannii Iron assimilation chemistry.chemical_compound NAD+ kinase 0912 Materials Engineering QD1-999 Oxazole |
| Zdroj: | ACS Omega, Vol 6, Iss 28, Pp 18537-18547 (2021) ACS Omega |
| ISSN: | 2470-1343 |
| Popis: | Acinetobacter baumannii is an opportunistic pathogen with a high mortality rate due to multi-drug-resistant strains. The synthesis and uptake of the iron-chelating siderophores acinetobactin (Acb) and preacinetobactin (pre-Acb) have been shown to be essential for virulence. Here, we report the kinetic and structural characterization of BauF, a flavin-dependent siderophore-interacting protein (SIP) required for the reduction of Fe(III) bound to Acb/pre-Acb and release of Fe(II). Stopped-flow spectrophotometric studies of the reductive half-reaction show that BauF forms a stable neutral flavin semiquinone intermediate. Reduction with NAD(P)H is very slow (k obs, 0.001 s-1) and commensurate with the rate of reduction by photobleaching, suggesting that NAD(P)H are not the physiological partners of BauF. The reduced BauF was oxidized by Acb-Fe (k obs, 0.02 s-1) and oxazole pre-Acb-Fe (ox-pre-Acb-Fe) (k obs, 0.08 s-1), a rigid analogue of pre-Acb, at a rate 3-11 times faster than that with molecular oxygen alone. The structure of FAD-bound BauF was solved at 2.85 Å and was found to share a similarity to Shewanella SIPs. The biochemical and structural data presented here validate the role of BauF in A. baumannii iron assimilation and provide information important for drug design. Published version |
| Databáze: | OpenAIRE |
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