7LRN

Structure of the Siderophore Interacting Protein from Acinetbacter baumannii

Summary for 7LRN

• Entry DOI: 10.2210/pdb7lrn/pdb
• Descriptor: NADPH-dependent ferric siderophore reductase, FLAVIN-ADENINE DINUCLEOTIDE (2 entities in total)
• Functional Keywords: siderophore-interacting protein, flavin binding, oxidoreductase
• Biological source: Acinetobacter baumannii
• Total number of polymer chains: 2
• Total formula weight: 70691.30

Authors

Tanner, J.J.,Korasick, D.A. (deposition date: 2021-02-16, release date: 2021-07-21, Last modification date: 2023-10-18)

Primary citation

Valentino, H.,Korasick, D.A.,Bohac, T.J.,Shapiro, J.A.,Wencewicz, T.A.,Tanner, J.J.,Sobrado, P.
Structural and Biochemical Characterization of the Flavin-Dependent Siderophore-Interacting Protein from Acinetobacter baumannii .
Acs Omega, 6:18537-18547, 2021

PubMed Abstract: 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 ( , 0.001 s) 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 ( , 0.02 s) and oxazole pre-Acb-Fe (ox-pre-Acb-Fe) ( , 0.08 s), 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 SIPs. The biochemical and structural data presented here validate the role of BauF in iron assimilation and provide information important for drug design.

PubMed: 34308084
DOI: 10.1021/acsomega.1c03047

Experimental method

X-RAY DIFFRACTION (2.85 Å)