1P0Z: Sensor Kinase Cita Binding Domain

The integral membrane sensor kinase CitA of Klebsiella pneumoniae is part of a two-component signal transduction system that regulates the transport and metabolism of citrate in response to its environmental concentration. Two-component systems are widely used by bacteria for such adaptive processes, but the stereochemistry of periplasmic ligand binding and the mechanism of signal transduction across the membrane remain poorly understood. The crystal structure of the CitAP periplasmic sensor domain in complex with citrate reveals a PAS fold, a versatile ligand-binding structural motif that has not previously been observed outside the cytoplasm or implicated in the transduction of conformational signals across the membrane. Citrate is bound in a pocket that is shared among many PAS domains but that shows structural variation according to the nature of the bound ligand. In CitAP, some of the citrate contact residues are located in the final strand of the central beta-sheet, which is connected to the C-terminal transmembrane helix. These secondary structure elements thus provide a potential conformational link between the periplasmic ligand binding site and the cytoplasmic signaling domains of the receptor.
PDB ID: 1P0ZDownload
MMDB ID: 24098
PDB Deposition Date: 2003/4/11
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.6  Å
Source Organism:
Similar Structures:
Biological Unit for 1P0Z: dimeric; determined by author
Molecular Components in 1P0Z
Label Count Molecule
Proteins (2 molecules)
Sensor Kinase Cita
Molecule annotation
Chemicals (9 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB