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Acta Crystallogr D Struct Biol. 2017 Jul 1;73(Pt 7):557-572. doi: 10.1107/S2059798317006349. Epub 2017 Jun 30.

Crystal structure of Yersinia pestis virulence factor YfeA reveals two polyspecific metal-binding sites.

Author information

1
Graduate Biomedical Sciences Microbiology Theme, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
2
Office of the Provost, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
3
Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
4
Department of Microbiology and Immunology and the Center for Predictive Medicine for Biodefense and Emerging Infectious Diseases, University of Louisville School of Medicine, Louisville, KY 40202, USA.
5
Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY 40536, USA.

Abstract

Gram-negative bacteria use siderophores, outer membrane receptors, inner membrane transporters and substrate-binding proteins (SBPs) to transport transition metals through the periplasm. The SBPs share a similar protein fold that has undergone significant structural evolution to communicate with a variety of differentially regulated transporters in the cell. In Yersinia pestis, the causative agent of plague, YfeA (YPO2439, y1897), an SBP, is important for full virulence during mammalian infection. To better understand the role of YfeA in infection, crystal structures were determined under several environmental conditions with respect to transition-metal levels. Energy-dispersive X-ray spectroscopy and anomalous X-ray scattering data show that YfeA is polyspecific and can alter its substrate specificity. In minimal-media experiments, YfeA crystals grown after iron supplementation showed a threefold increase in iron fluorescence emission over the iron fluorescence emission from YfeA crystals grown from nutrient-rich conditions, and YfeA crystals grown after manganese supplementation during overexpression showed a fivefold increase in manganese fluorescence emission over the manganese fluorescence emission from YfeA crystals grown from nutrient-rich conditions. In all experiments, the YfeA crystals produced the strongest fluorescence emission from zinc and could not be manipulated otherwise. Additionally, this report documents the discovery of a novel surface metal-binding site that prefers to chelate zinc but can also bind manganese. Flexibility across YfeA crystal forms in three loops and a helix near the buried metal-binding site suggest that a structural rearrangement is required for metal loading and unloading.

KEYWORDS:

X-ray crystallography; Yersinia pestis; YfeA; plague; polyspecificity; substrate-binding protein (SBP); transition-metal homeostasis; virulence factor

PMID:
28695856
PMCID:
PMC5505154
DOI:
10.1107/S2059798317006349
[Indexed for MEDLINE]
Free PMC Article

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