Reference Work Entry

Encyclopedia of Biophysics

pp 573-577

Electron Cryo-microscopy of Molecular Machines

  • Junjie ZhangAffiliated withDepartment of Structural Biology, Stanford University Email author 
  • , Wah ChiuAffiliated withNational Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine


Electron Cryo-microscopy; Electron microscopy; Molecular motors; Single particle electron microscopy


Molecular machine: A large complex made up of multiple copies of proteins and/or nucleic acids with a molecular size ranging from hundreds of kDa to tens of MDa. Examples of molecular machines are virus, ribosome, chaperonin, etc.

Electron cryo-microscopy (Cryo-EM): A structural method uses electron microscope to record images of frozen, hydrated specimens and uses computational procedures to reconstruct its three-dimensional density.

Single particle cryo-EM: A special application of cryo-EM where the specimen is a noncrystalline type embedded in a thin layer of vitreous ice as individual particles in random orientations.


Single-particle electron cryo-microscopy (cryo-EM) is an emerging structural biophysics technique for imaging individual molecular machines. Advantages of the cryo-EM imaging technique are that it can be used to d ...

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