3SN9

Fic protein from NEISSERIA MENINGITIDIS mutant S182A/E186A in complex with AMPPNP

Summary for 3SN9

• Entry DOI: 10.2210/pdb3sn9/pdb
• Related: 3s6a 3se5
• Descriptor: Cell filamentation protein Fic-related protein, PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER (2 entities in total)
• Functional Keywords: ampylation, adenylylation, transferase
• Biological source: Neisseria meningitidis
• Total number of polymer chains: 16
• Total formula weight: 360884.98

Authors

Goepfert, A.,Stanger, F.,Schirmer, T. (deposition date: 2011-06-29, release date: 2012-01-25, Last modification date: 2023-09-13)

Primary citation

Engel, P.,Goepfert, A.,Stanger, F.V.,Harms, A.,Schmidt, A.,Schirmer, T.,Dehio, C.
Adenylylation control by intra- or intermolecular active-site obstruction in Fic proteins.
Nature, 482:107-110, 2012

PubMed Abstract: 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 α-helix (α(inh)) with a conserved (S/T)XXXE(G/N) motif, and that in this mechanism the invariable glutamate competes with ATP γ-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 α(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 α(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 α(inh) is universal and conserved through evolution, as the inhibitory motif is present in ∼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 α(inh) with the FIC active site.

PubMed: 22266942
DOI: 10.1038/nature10729

Experimental method

X-RAY DIFFRACTION (3.03 Å)