Joachim Frank's laboratory develops methods of cryo-electron microscopy and three-dimensional reconstruction to study the mechanism of protein biosynthesis.
Ribosome Dynamics During Translation Studied by Cryoelectron Microscopy
Cryoelectron microscopy (cryo-EM) and computer image processing are employed to study the structure and dynamics of the ribosome during translation. The ribosome is a highly complex molecular machine that goes through a multistep processing cycle (the elongation cycle) for each amino acid to be added to the growing polypeptide chain. Although x-ray crystallography can give information on the atomic structure, cryo-EM and single-particle reconstruction is unique in its ability to visualize ligand binding and conformational changes of such a large molecular machine. The student will work on a ribosome sample where the ribosome (from bacteria or eukaryotes) is in a particular processing state or a series of states. He/she will learn how to prepare a specimen, how to operate an electron microscope, and how to use image-processing software to analyze and classify electron micrographs and obtain a three-dimensional reconstruction from tens of thousands of individual ribosome images that are computer selected. This reconstruction is then analyzed by computer docking and flexible fitting of x-ray structures, as well as bioinformatics tools, to define the binding position of the ligand or quantify the conformational changes of the ribosome. These results will contribute toward an understanding of how the ribosome works and how translation is controlled and regulated in the cell. The student will also attend weekly group meetings on issues of translation and image processing, and interpretation of cryo-EM maps.