3hru | pdb_00003hru

Crystal Structure of ScaR with bound Zn2+

spinqualitylabelsall models 3hru, resolution 2.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3hru is a 2 chain structure with sequence from Streptococcus gordonii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: SO4, ZN Related: 3hrt, 3hrs Gene: scaR (Streptococcus gordonii) Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The streptococcal coaggregation regulator (ScaR) of Streptococcus gordonii is a manganese-dependent transcriptional regulator. When intracellular manganese concentrations become elevated, ScaR represses transcription of the scaCBA operon, which encodes a manganese uptake transporter. A member of the DtxR/MntR family of metalloregulators, ScaR shares sequence similarity with other family members, and many metal-binding residues are conserved. Here, we show that ScaR is an active dimer, with two dimers binding the 46 base pair scaC operator. Each ScaR subunit binds two manganese ions, and the protein is activated by a variety of other metal ions, including Cd(2+), Co(2+), and Ni(2+) but not Zn(2+). The crystal structure of apo-ScaR reveals a tertiary and quaternary structure similar to its homologue, the iron-responsive regulator DtxR. While each DtxR subunit binds a metal ion in two sites, labeled primary and ancillary, crystal structures of ScaR determined in the presence of Cd(2+) and Zn(2+) show only a single occupied metal-binding site that is novel to ScaR. The site analogous to the primary site in DtxR is unoccupied, and the ancillary site is absent from ScaR. Instead, metal ions bind to ScaR at a site labeled "secondary", which is composed of Glu80, Cys123, His125, and Asp160 and lies roughly 5 A away from where the ancillary site would be predicted to exist. This difference suggests that ScaR and its closely related homologues are activated by a mechanism distinct from that of either DtxR or MntR. Characterization and structure of the manganese-responsive transcriptional regulator ScaR.,Stoll KE, Draper WE, Kliegman JI, Golynskiy MV, Brew-Appiah RA, Phillips RK, Brown HK, Breyer WA, Jakubovics NS, Jenkinson HF, Brennan RG, Cohen SM, Glasfeld A Biochemistry. 2009 Nov 3;48(43):10308-20. PMID:19795834 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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