High-pressure solution X-ray scattering of protein using a hydrostatic cell with diamond windows.

A hydrostatic high-pressure cell (maximum pressure 700 MPa) with synthetic diamond windows is applied to measure small-angle X-ray scattering of a protein at high pressure. Use of the present cell allows an accurate solvent background correction, providing quantitative analyses. The performance of the present cell for X-ray scattering is shown by using lysozyme as a sample solution. From the Guinier plot, values of the radius of gyration of lysozyme are evaluated to be 15.31 +/- 0.09 A at 1 atm (0.10 MPa) and 14.80 +/- 0.15 A at 400 MPa.