3HCQ: Structural Analysis Of The Choline Binding Protein Chox In A Semi- Closed And Ligand-Free Conformation

The periplasmic ligand-binding protein ChoX is part of the ABC transport system ChoVWX that imports choline as a nutrient into the soil bacterium Sinorhizobium meliloti. We have recently reported the crystal structures of ChoX in complex with its ligands choline and acetylcholine and the structure of a fully closed but substrate-free state of ChoX. This latter structure revealed an architecture of the ligand-binding site that is superimposable to the closed, ligand-bound form of ChoX. We report here the crystal structure of ChoX in an unusual, ligand-free conformation that represents a semi-closed form of ChoX. The analysis revealed a subdomain movement in the N-lobe of ChoX. Comparison with the two well-characterized substrate binding proteins, MBP and HisJ, suggests the presence of a similar subdomain in these proteins.
PDB ID: 3HCQDownload
MMDB ID: 77315
PDB Deposition Date: 2009/5/6
Updated in MMDB: 2009/10
Experimental Method:
x-ray diffraction
Resolution: 2.89  Å
Source Organism:
Similar Structures:
Biological Unit for 3HCQ: monomeric; determined by author and by software (PISA)
Molecular Components in 3HCQ
Label Count Molecule
Protein (1 molecule)
Putative Choline ABC Transporter, Periplasmic Solute- Binding Component
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB