低解像度電子顕微鏡画像からの原子モデル構造の構築

Atomic model building from low resolution electron microscopy images

松本 淳; 高木 淳一*; 岩崎 憲治*

Matsumoto, Atsushi; Takagi, Junichi*; Iwasaki, Kenji*

We have developed a computational technique to build an atomic model from an electron microscopy (EM) image of a biological molecule. In this technique, many atomic models with different conformations of the molecule are prepared first by deforming the X-ray crystal structure or the modeled structure using a computational technique. Then, each atomic model is projected to many different directions and projection images are obtained. Finally, they are compared to the EM image. The atomic models with the projection images similar to the EM image are regarded as the candidates for the atomic structure of the molecule. This technique was applied to the EM images of integrin. Integrin is a membrane protein with a huge extracellular domain, and participates in cell-cell and cell-extracellular-matrix interactions. The X-ray crystal structure of the molecule is already solved. However, it is often very different form those seen in the EM images. By the conventional computational approach, it is difficult to reach the EM structure from the X-ray structure. Thus, we employed a coarse-grained model to simulate the large-scale conformational change.