Atomic model building from low resolution electron microscope images of integrin

インテグリン分子の低解像度電子顕微鏡画像から原子モデルを構築する

松本 淳; 岩崎 憲治*; 高木 淳一*

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

We have developed a computational approach to build an atomic model from an electron microscope (EM) image of proteins. In this approach, many atomic models are built first by deforming the X-ray crystal structure of the protein using a computational technique. Then, projection images of each atomic model to many different directions are generated. 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 protein from which the EM image was obtained. This approach was applied to the EM images of integrin. The X-ray crystal structure of integrin was solved for the closed conformation, while many EM images were obtained for the open conformation. The difference of the two conformations is so large that it is difficult to build the atomic model for the EM conformations by deforming the X-ray crystal structure using conventional computational techniques. Thus, we have used the coarse-grained model of the X-ray crystal structure to simulate the large-scale conformational change.