Subtomogram analysis: The sum of a tomogram’s particles reveals molecular structure in situ

Graphical abstract

Highlights

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  Cryo-electron tomography depicts the biochemical machinery inside the cell at molecular detail.

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  Subtomogram averaging overcomes the beam sensitivity of biological macromolecules and enables resolving macromolecules that occur in multiple copies at much higher resolution than the individual observations.

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  Key developments of this approach were pursued in the laboratory of Wolfgang Baumeister.

Abstract

Cryo-electron tomography is uniquely suited to provide insights into the molecular architecture of cells and tissue in the native state. While frozen hydrated specimens tolerate sufficient electron doses to distinguish different types of particles in a tomogram, the accumulating beam damage does not allow resolving their detailed molecular structure individually. Statistical methods for subtomogram averaging and classification that coherently enhance the signal of particles corresponding to copies of the same type of macromolecular allow obtaining much higher resolution insights into macromolecules. Here, I review the developments in subtomogram analysis at Wolfgang Baumeister’s laboratory that make the dream of structural biology in the native cell become reality.