Mechanistic insights into metal ion activation and operator recognition by the ferric uptake regulator

Abstract

Ferric uptake regulator (Fur) plays a key role in the iron homeostasis of prokaryotes, such as bacterial pathogens, but the molecular mechanisms and structural basis of Fur–DNA binding remain incompletely understood. Here, we report high-resolution structures of Magnetospirillum gryphiswaldense MSR-1 Fur in four different states: apo-Fur, holo-Fur, the Fur–feoAB1 operator complex and the Fur–Pseudomonas aeruginosa Fur box complex. Apo-Fur is a transition metal ion-independent dimer whose binding induces profound conformational changes and confers DNA-binding ability. Structural characterization, mutagenesis, biochemistry and in vivo data reveal that Fur recognizes DNA by using a combination of base readout through direct contacts in the major groove and shape readout through recognition of the minor-groove electrostatic potential by lysine. The resulting conformational plasticity enables Fur binding to diverse substrates. Our results provide insights into metal ion activation and substrate recognition by Fur that suggest pathways to engineer magnetotactic bacteria and antipathogenic drugs.

Structural and functional studies of the metalloregulator Fur identify a promoter-binding mechanism and its role in Francisella tularensis virulence

“…Mutations of the FurBox (FurBox m , see Supplementary Fig. 2) targeting four bases previously shown to be crucial for the specific Fur/DNA interactions 31 , three of them being involved in interactions with Tyr56 28,29 , resulted in the conservation of the tetramer without apparition of dimers.…”

BosR Is A Novel Fur Family Member Responsive to Copper and Regulating Copper Homeostasis in Borrelia burgdorferi

“…To date, a total of 21 crystal structures have been reported for 12 members of the Fur family (22,(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38). With the exception of the E. coli Fur structure, which is of an amino-terminal truncate, all the other structures are of full-length proteins.…”

“…With the exception of the E. coli Fur structure, which is of an amino-terminal truncate, all the other structures are of full-length proteins. Notably, structures of the E. coli Zur and the Magnetospirillum gryphiswaldense Fur are solved in complex with target DNA molecules, offering insights into DNA recognition by the Fur family of regulators (36,38). All structures indicate that members of the Fur family of regulators exist as homodimers, with each subunit consisting of two distinct domains, an amino-terminal DNA-binding domain (DBD) and a carboxyl-terminal dimerization domain (DD), connected by a flexible hinge region.…”

Iron Response Regulator Protein IrrB in Magnetospirillum gryphiswaldense MSR-1 Helps Control the Iron/Oxygen Balance, Oxidative Stress Tolerance, and Magnetosome Formation

“…Fur (encoded by the MGMSRv2_3137 gene) is a real Fur protein and regulates the expression of genes involved in iron and oxygen metabolism (11). It has a unique sulfur-rich center that contains Cys9, Met14, and Met16 and is oxygen sensitive (21). IrrB has Irr characteristics and may be stable under conditions of iron deficiency.…”

“…However, fur did not show any striking change in expression. A recent report indicates that Fur functions as a real Fur protein, like Fur-Pa, and differs from Irr proteins (21).…”