[14] Preparation of new two- and three-dimensional crystal forms of bacteriorhodopsin

摘要: Publisher Summary This chapter discusses the preparation of new two- and three-dimensional crystal forms bacteriorhodopsin. The recent crystallization bacteriorhodopsin gives some hope that standard X-ray methods can be applied to membrane proteins. First step is solubilization In this purple membranes are stirred in 1.3 ml 1.2% β-n-octyl glucoside containing sodium phosphate buffer at 30 °. After 3 days stirring, nonsolubilized spun down 150,000 g for 45 min. solution then brought a concentration 0.7 M ammonium sulfate or phosphate, pH 5–5.5, by addition saturated solutions concentrated threefold over phosphorus pentoxide an evacuated desiccator. Crystallization achieved vapor diffusion respective against 2.5 4.7. crystals, which probably still contain most lipids membrane, become disordered on removal octyl glucoside, as seen from loss strict chromophore orientation parallel long needle axis.