4zcm | pdb_00004zcm

Crystal Structure of Escherichia coli GTPase BipA/TypA Complexed with ppGpp

spinqualitylabelsall models 4zcm, resolution 3.31Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4zcm is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: G4P, MG, NCO Related: 4zci, 4zck, 4zcl Resources: FirstGlance, OCA, RCSB, PDBsum Function [TYPA_ECOLI] Probably interacts with the ribosomes in a GTP dependent manner. GTPase that mediates interactions between enteropathogenic E.coli (EPEC) and epithelial cells. Publication Abstract from PubMed The translational GTPase BipA regulates the expression of virulence and pathogenicity factors in several eubacteria. BipA-dependent expression of virulence factors occurs under starvation conditions, such as encountered during infection of a host. Under these conditions, BipA associates with the small ribosomal subunit. BipA also has a second function to promote the efficiency of late steps in biogenesis of large ribosomal subunits at low temperatures, presumably while bound to the ribosome. During starvation, the cellular concentration of stress alarmone guanosine-3', 5'-bis pyrophosphate (ppGpp) is increased. This increase allows ppGpp to bind to BipA and switch its binding specificity from ribosomes to small ribosomal subunits. A conformational change of BipA upon ppGpp binding could explain the ppGpp regulation of BipA's binding specificity. Here, we present the structures of the full-length BipA from Escherichia coli in apo, GDP-, and ppGpp-bound forms. The crystal structure and small-angle X-ray scattering data of the protein with bound nucleotides, together with a thermodynamic analysis of the binding of GDP and of ppGpp to BipA, indicates that the ppGpp-bound form of BipA adopts the structure of the GDP form. This suggests furthermore, that the switch in binding preference only occurs when both ppGpp and the small ribosomal subunit are present. This molecular mechanism would allow BipA to interact with both the ribosome and the small ribosomal subunit during stress response. Structural and Functional Analysis of BipA, a Regulator of Virulence in enteropathogenic Escherichia coli.,Fan H, Hahm J, Diggs S, Perry JJ, Blaha G J Biol Chem. 2015 Jul 10. pii: jbc.M115.659136. PMID:26163516 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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