Crystallization of a complex between a novel C-terminal transmitter, HPt domain, of the anaerobic sensor kinase ArcB and the chemotaxis response regulator CheY

The histidine-containing phosphotransfer (HPt) domain at the C-terminus of the anaerobic sensor kinase ArcB has been cocrystallized with the chemotaxis response regulator CheY by a hanging-drop vapor-diffusion method. Crystals belong to space group P2₁2₁2₁ with unit-cell dimensions a = 55.32, b = 76.29 and c = 83.89 Å, with one molecule in the crystallographic asymmetric unit. The crystals diffract to 2.7 Å resolution. This is the first crystallization of a protein-protein complex formed by a transmitter domain of sensor kinase and a receiver domain of response regulator in the two-component signal-transduction system.