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    Table of contents
    1. 1. Protein Summary
    2. 2. Ligand Summary
    3. 3. References

    Title Structural and functional characterizations of SsgB, a conserved activator of developmental cell division in morphologically complex actinomycetes. J.Biol.Chem. 284 25268-25279 2009
    Site JCSG
    PDB Id 3cm1 Target Id 361176
    Molecular Characteristics
    Source Thermobifida fusca yx
    Alias Ids TPS1464,YP_290167.1, PF04686, 332036 Molecular Weight 15250.26 Da.
    Residues 138 Isoelectric Point 4.46
    Sequence msssgtsitcevglqlivpdrapvplvarldysvddpyairaafhvgddepvewifarelltvgiiret gegdvriwpsqdgkermvnialsspfgqarfhaqvaplseflhrtyelvpagqesdyididaeiaehls
      BLAST   FFAS

    Structure Determination
    Method XRAY Chains 1
    Resolution (Å) 2.60 Rfree 0.270
    Matthews' coefficent 2.97 Rfactor 0.230
    Waters Solvent Content 58.56

    Ligand Information


    Google Scholar output for 3cm1
    1. Multifrequency EPR spectroscopy: A toolkit for the characterization of mono-and di-nuclear metal ion centers in complex biological systems
    GR Hanson - Structure and Function, by Comba, Peter, ISBN 978 , 2010 - books.google.com

    Protein Summary

    YP_290167.1 encodes a small protein which is homologous to sporulation control protein SsgA, and is a first solved representative of its family of SsgA-like proteins (SALPs) or PFAM family (PF04686). SsgA functions as cell division activator  and is essential for sporulation of Streptomyces coelicolor. In vivo, it affects the peptidoglycan of the cell wall. SALPs proteins are thought to play the same role in other actinomycetes.  The SsgA family is extensively studied, with over 20 papers in Medline, but its exact function in sporulation is still not understood at the molecular level (reviewed in 1).

    The crystal structure revealed unexpected structural similarity to a class of a so-called "whirly" ssDNA-binding transcriptional regulator fold. Our SALP structure is highly similar to mitochondrial RNA binding proteins 2 (pdb id 2gid, rmsd ~2). In contrast to its homologs which function as dimers or tetramers, YP_290167.1 is likely to function as a trimer.

    This is a first crystal structure of a memeber of a SALPs family, its structural similarities to ssDNA or RNA binding proteins offer interesting clues to its function inside the cell. Based on the structural similarity, the putative ssDNA binding site is likely to locate at the monomer-monomer interface (Figure below) with the following R/K/H residues are implicated:  29, 41,45, 67,75. This is a first ssDNA or RNA binding protein that may work as a trimer.

    NOTE:  JCSG also solved another "whirly" protein 2it9 and 2nvn.

    Piotr Kozbial's contribution (19-MAR-2008):

    SsgA-like sporulation-specific cell division proteins: SsgA and SsgB are essential for sporulation-specific cell division in S. coelicolor, SsgC-G are responsible for correct DNA segregation/condensation (SsgC), spore wall synthesis (SsgD), autolytic spore separation (SsgE, SsgF), or exact septum localisation (SsgG) [Noens et al. (2005) Mol Microbiol 58: 929-944] End of Piotr Kozbial's contribution

    Ligand Summary





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