Structure of macromolecule determines function. The Chang lab is deeply interested and devoted in understanding biology from structural perspective. Distinct from most of the other structural biology groups working with purified macromolecules, the Chang lab utilizes Electron Cryotomography (A.K.A. cryo-electron tomography), an emerging powerful cryo-electron microscopy imaging technique, to study the structure and mechanism of macromolecular nanomachines directly inside cells. In the native cellular environment, electron cryotomography reveals not only native conformations and assemblies of the nanomachines as they are conducting functions, but also their distribution, orientations and interactions to other cellular components – thus enabling studies of Structural Cell Biology and Molecular Sociology.