4hv5 | pdb_00004hv5

Structure of the MNTR FE2+ complex with E site metal binding

spinqualitylabelsall models 4hv5, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4hv5 is a 2 chain structure with sequence from Bacillus subtilis subsp. subtilis str. 168. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EPE, FE2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MNTR_BACSU Central regulator of manganese homeostasis. In the presence of manganese, it mediates repression of the manganese transporter MntH; under low manganese conditions, it activates the transcription of the mntABCD operon. Publication Abstract from PubMed The manganese transport regulator (MntR) represses the expression of genes involved in manganese uptake in Bacillus subtilis. It selectively responds to Mn(2+) and Cd(2+) over other divalent metal cations, including Fe(2+), Co(2+), and Zn(2+). Previous work has shown that MntR forms binuclear complexes with Mn(2+) or Cd(2+) at two binding sites, labeled A and C, that are separated by 4.4 A. Zinc activates MntR poorly and binds only to the A site, forming a mononuclear complex. The difference in metal binding stoichiometry suggested a mechanism for selectivity in MntR. Larger metal cations are strongly activating because they can form the binuclear complex, while smaller metal ions cannot bind with the geometry needed to fully occupy both metal binding sites. To investigate this hypothesis, structures of MntR in complex with two other noncognate metal ions, Fe(2+) and Co(2+), have been determined. Each metal forms a mononuclear complex with MntR with the metal ion bound in the A site, supporting the conclusions drawn from the Zn(2+) complex. Additionally, we investigated two site-specific mutants of MntR, E11K and H77A, that contain substitutions of metal binding residues in the A site. While metal binding in each mutant is significantly altered relative to that of wild-type MntR, both mutants retain activity and selectivity for Mn(2+) in vitro and in vivo. That observation, coupled with previous studies, suggests that the A and C sites both contribute to the selectivity of MntR. Roles of the A and C Sites in the Manganese-Specific Activation of MntR.,McGuire AM, Cuthbert BJ, Ma Z, Grauer-Gray KD, Brunjes Brophy M, Spear KA, Soonsanga S, Kliegman JI, Griner SL, Helmann JD, Glasfeld A Biochemistry. 2013 Jan 29;52(4):701-13. doi: 10.1021/bi301550t. Epub 2013 Jan 17. PMID:23298157 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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