4AWX : Moonlighting functions of FeoC in the regulation of ferrous iron transport in Feo

  • Yen Lan Hsu (Contributor)
  • Kuo Wei Hung (Contributor)
  • Tai-Huang Huanga (Contributor)
  • Chwan Deng Hsiao (Contributor)
  • Tzu Hsuan Juan (Contributor)
  • Jia-Yin Tsai (Contributor)



Experimental Technique/Method:X-RAY DIFFRACTION
Classification:METAL TRANSPORT
Release Date:2013-03-06
Deposition Date:2012-06-06
Revision Date:
Molecular Weight:38685.22
Macromolecule Type:Protein
Residue Count:351
Atom Site Count:2422

Feo is a transport system commonly used by bacteria to acquire environmental Fe(2+). It consists of three proteins: FeoA, FeoB, and FeoC. FeoB is a large protein with a cytosolic N-terminal domain (NFeoB) that contains a regulatory G protein domain and a helical S domain. The C-terminal region of FeoB is a transmembrane domain that likely acts as the Fe(2+) permease. NFeoB has been shown to form a trimer pore that may function as an Fe(2+) gate. FeoC is a small winged-helix protein that possesses four conserved cysteine residues with a consensus sequence that likely provides binding sites for the [Fe-S] cluster. Therefore, FeoC is presumed to be an [Fe-S] cluster-dependent regulator that directly controls transcription of the feo operon. Despite the apparent significance of the Feo system, however, the function of FeoC has not been experimentally demonstrated. Here, we show that Klebsiella pneumoniae FeoC (KpFeoC) forms a tight complex with the intracellular N-terminal domain of FeoB (KpNFeoB). The crystal structure of the complex reveals that KpFeoC binds to KpNFeoB between the switch II region of the G protein domain and the effector S domain and that the long KpFeoC W1 loop lies above the KpNFeoB nucleotide-binding site. These interactions suggest that KpFeoC modulates the guanine nucleotide-mediated signal transduction process. Moreover, we showed that binding of KpFeoC disrupts pore formation by interfering with KpNFeoB trimerization. These results provide strong evidence suggesting that KpFeoC plays a crucial role in regulating Fe(2+) transport in Klebsiella pneumonia in addition to the presumed gene regulator role.
Date made available2013 Mar 6
PublisherUnknown Publisher

Cite this