Purification, crystallization and preliminary crystallographic studies of the ligand-binding domain of a plant vacuolar sorting receptor.
Vacuolar sorting receptor (VSR) proteins bind soluble protein ligands in a sequence-specific manner and target them to the lytic vacuole in plant cells. A VSR from Arabidopsis thaliana, AtBP80b, has been successfully purified after heterologous expression in Drosophila S2 cells. The AtBP80b protein (560 amino acids) was crystallized by the hanging-drop method with a PEG 400-based precipitant. Preliminary X-ray diffraction studies of an AtBP80b crystal showed that it belongs to the cubic space group P2(1)3 (or P4(2)32) and has unit-cell parameters a = b = c = 145.9 A. Crystals of the VSR diffract beyond 2.5 A resolution.