3shg

VBHT Fic protein from BARTONELLA SCHOENBUCHENSIS in complex with VBHA antitoxin

spinqualitylabelsall models 3shg, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3shg is a 2 chain structure with sequence from Barsr. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: TLA Related: 2jk8 Gene: B11C_100026 (BARSR), B11C_100027 (BARSR) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [VBHT_BARSR] Toxic component of a toxin-antitoxin (TA) module VbhT-VbhA. Adenylyltransferase involved in virulence by mediating the addition of adenosine 5'-monophosphate (AMP) to specific residue of host GTPases. The resulting AMPylation affects GTPases, impairing actin assembly in infected cells. [VBHA_BARSR] Antitoxin component of a toxin-antitoxin (TA) module VbhT-VbhA. Acts by inhibiting the adenylyltransferase activity of VbhT; competes with ATP-binding and prevents productive ATP-binding to VbhT. Publication Abstract from PubMed Fic proteins that are defined by the ubiquitous FIC (filamentation induced by cyclic AMP) domain are known to catalyse adenylylation (also called AMPylation); that is, the transfer of AMP onto a target protein. In mammalian cells, adenylylation of small GTPases through Fic proteins injected by pathogenic bacteria can cause collapse of the actin cytoskeleton and cell death. It is unknown how this potentially deleterious adenylylation activity is regulated in the widespread Fic proteins that are found in all domains of life and that are thought to have critical roles in intrinsic signalling processes. Here we show that FIC-domain-mediated adenylylation is controlled by a conserved mechanism of ATP-binding-site obstruction that involves an inhibitory alpha-helix (alpha(inh)) with a conserved (S/T)XXXE(G/N) motif, and that in this mechanism the invariable glutamate competes with ATP gamma-phosphate binding. Consistent with this, FIC-domain-mediated growth arrest of bacteria by the VbhT toxin of Bartonella schoenbuchensis is intermolecularly repressed by the VbhA antitoxin through tight binding of its alpha(inh) to the FIC domain of VbhT, as shown by structure and function analysis. Furthermore, structural comparisons with other bacterial Fic proteins, such as Fic of Neisseria meningitidis and of Shewanella oneidensis, show that alpha(inh) frequently constitutes an amino-terminal or carboxy-terminal extension to the FIC domain, respectively, partially obstructing the ATP binding site in an intramolecular manner. After mutation of the inhibitory motif in various Fic proteins, including the human homologue FICD (also known as HYPE), adenylylation activity is considerably boosted, consistent with the anticipated relief of inhibition. Structural homology modelling of all annotated Fic proteins indicates that inhibition by alpha(inh) is universal and conserved through evolution, as the inhibitory motif is present in approximately 90% of all putatively adenylylation-active FIC domains, including examples from all domains of life and from viruses. Future studies should reveal how intrinsic or extrinsic factors modulate adenylylation activity by weakening the interaction of alpha(inh) with the FIC active site. Adenylylation control by intra- or intermolecular active-site obstruction in Fic proteins.,Engel P, Goepfert A, Stanger FV, Harms A, Schmidt A, Schirmer T, Dehio C Nature. 2012 Jan 22;482(7383):107-10. doi: 10.1038/nature10729. PMID:22266942 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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