Wolfgang Baumeister talks
with ScienceWatch.com and answers a few questions
about this month's Fast Moving Front in the field of
Article: Macromolecular architecture in eukaryotic
cells visualized by cryoelectron tomography
Authors: Medalia, O;Weber, I;Frangakis, AS;Nicastro,
Journal: SCIENCE, 298 (5596): 1209-1213 NOV 8 2002
Addresses: Max Planck Inst Biochem, D-82152 Martinsried,
Max Planck Inst Biochem, D-82152 Martinsried,
Why do you think your paper is highly
I think it became immediately clear that this paper marked a breakthrough
in demonstrating for the first time that cryoelectron (cryo-ET)
tomography—an emerging imaging technique with unique potential for
molecular cell biology—was capable of visualizing molecular
structures in intact cells under close-to-life conditions.
It became clear that this method had the unique potential to bridge the
existing divide between cellular and molecular structural studies. This was
also recognized by the editors of Science, who selected it as one
of the breakthroughs of the year across all fields of science.
Does it describe a new discovery, methodology, or
synthesis of knowledge?
"I think it became
immediately clear that this
paper marked a breakthrough
in demonstrating for the
first time that cryoelectron
It described the first application of a technique we had developed in
previous years to a eukaryotic cell grown on an electron microscopy (EM)
Would you summarize the significance of your paper
in layman's terms?
The methods traditionally used in biological electron microscopy of cells
and tissues are prone to artifacts. The artifacts resulting from chemical
fixation, dehydration, and contrasting agents are completely eliminated in
Cryo-ET tomography combines the close-to-life preservation of biological
samples with the power of three-dimensional imaging. It allows studying the
structural organization of cells in a non-invasive manner at molecular
resolution (2-4 nm). Tomograms of this kind contain a wealth of information
about supramolecular architecture and molecular interaction networks. The
challenge ahead of us is to mine this imposing amount of information.
How did you become involved in this research and
were there any particular problems encountered along the way?
We began to develop cryo-ET tomography already in the late '80s—in
the face of strong skepticism. Many in the field regarded it as simply not
feasible to obtain high-resolution tomograms of biological material
embedded in vitreous ice, given the radiation sensitivity of such samples.
Major technical developments were necessary to make it possible, in
particular the development of smart software for the automated recording of
tomograms in a low-dose regime.
Where do you see your research leading in the
With the improvements in resolution which we can realistically expect will
come along in the next few years, and with more powerful computational
tools for the interpretation of the tomograms, it will become possible to
map the molecular landscape inside cells in a comprehensive manner. This
will enable us to study molecular machines and their functional environment
in action and also to reveal molecular interaction networks—the
molecular sociology of the cell. Visual proteomics will therefore play a
major role in cell biology in the years to come.
Prof. Dr. Wolfgang Baumeister
Director of the Department of Molecular Structural Biology
Max Planck Institute for Biochemistry
Keywords: cryoelectron tomography, biological
electron microscopy cells tissues, artifacts, chemical fixation,
dehydration, contrasting agents, cryopreparations, close-to-life
preservation biological samples, three-dimensional imaging, tomograms,
supramolecular architecture, molecular interaction networks, molecular
landscape, molecular machines, visual proteomics.