R-CCS Cafe 第200回 第2部

In order to analyze the functions and interactions of biomolecules at the molecular level, it is necessary to elucidate the detailed three-dimensional (3D) structure of biomolecules. Single-particle 3D structure analysis using X-ray free electron laser (XFEL) is a new structural biology technique that allows observation of biomolecular complexes and tissues that are difficult to crystallize in a state close to nature. However, even using intensive XFEL beam, diffraction intensity obtained from a single biomolecule is still weak, and the S/N ratio of the diffraction pattern is small. In order to restore the 3D structure with the expected resolution, it is necessary to estimate the requirement for the quantity and quality of the diffraction patterns. For this purpose, we tried to reconstruct the 3D structure of ribosome using the simulation diffraction pattern sets, consisting of the different number of patterns created by different beam intensities. In this presentation, I will show how the resolution of the reconstructed 3D structure depends on the quantity and quality of the diffraction patterns, which indicate the minimum requirement of XFEL experimental conditions to obtain the diffraction patterns to reconstruct the molecular structure with several nanometers resolution. Also, I will introduce our recent results of restoration of 3D-structure of gold nano-particle from the diffraction patterns obtained by XFEL experiment.