4BES: Crystal Structure Of The Legionella Pneumophila Fic Domain- Containing Effector Ankx Protein In Complex With Cytidine Monophosphate And Phosphocholine

The FIC motif and the eukaryotic-like ankyrin repeats are found in many bacterial type IV effectors, yet little is known about how these domains enable bacteria to modulate host cell functions. Bacterial FIC domains typically bind ATP and transfer adenosine monophosphate moiety onto target proteins. The ankyrin repeat-containing protein AnkX encoded by the intracellular pathogen Legionella pneumophila is unique in that its FIC domain binds to CDP-choline and transfers a phosphocholine residue onto proteins in the Rab1 GTPase family. By determining the structures of unbound AnkX and AnkX with bound CDP-choline, CMP/phosphocholine and CMP, we demonstrate that the orientation of substrate binding in relation to the catalytic FIC motif enables this protein to function as a phosphocholinating enzyme rather than a nucleotidyl transferase. Additionally, the structure reveals that the ankyrin repeats mediate scaffolding interactions that resemble those found in protein-protein interactions, but are unprecedented in intramolecular interactions. Together with phosphocholination experiments, our structures unify a general phosphoryl transferase mechanism common to all FIC enzymes that should be conserved from bacteria to human.
PDB ID: 4BESDownload
MMDB ID: 109339
PDB Deposition Date: 2013/3/12
Updated in MMDB: 2013/05
Experimental Method:
x-ray diffraction
Resolution: 2.54  Å
Source Organism:
Similar Structures:
Biological Unit for 4BES: dimeric; determined by author and by software (PISA)
Molecular Components in 4BES
Label Count Molecule
Proteins (2 molecules)
Phosphocholine Transferase Ankx(Gene symbol: legA8)
Molecule annotation
Chemicals (10 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB