Synchrotron Diffraction of Multilayered LS PGA Films after Heating and Cooling

Claudio Nicolini, Wright John and Eugenia Pechkova


X-ray diffraction patterns of multilayered Langmuir-Schaefer (LS) film of penicillin G acylase (PGA) enzyme were acquired at the ID11 of Synchrotron Radiation at ESRF (Grenoble, France). In addition to what shown by GISAXS at ID13 and by AFM, the ID11 beamline appears capable to monitor the diffraction and structural properties of the Langmuir-Shaefer multilayered PGA enzyme film similar to what apparent in the corresponding PGA crystals. The dramatic increase of long-range order in the LB multi-layered enzyme films after heating and cooling, made previously apparent by grazing incidence small angle X-ray scattering using ID13 microbeam, was here utilized at the ID11 beamline to yield unique diffraction patterns of the PGA LB linked to the enzyme atomic structure. This could open the way to bypass the bottleneck of protein crystallization which is leaving still unsolved large part of important proteins, like the membrane ones.