3hcq

Publication Abstract from PubMed

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.

Structural analysis of the choline-binding protein ChoX in a semi-closed and ligand-free conformation.,Oswald C, Smits SH, Hoing M, Bremer E, Schmitt L Biol Chem. 2009 Nov;390(11):1163-70. PMID:19642870^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.