What do you understand by Cryo-Electron Microscopy (cryo-EM). What are the advantages of this technology as compared to older available methods of determining bio-molecular structure?

What do you understand by Cryo-Electron Microscopy (cryo-EM). What are the advantages of this technology as compared to older available methods of determining bio-molecular structure?

Approach:

  • Introduce with Cryo-EM and why it was in news (2017 Nobel Prize in Chemistry)
  • Discuss its significance as to how this technique is different from available methodologies.
  • Conclude appropriately
Model Answer :

Cryo-EM is a technology that allows researchers to construct three-dimensional images of sample microscopic objects at super-cold (cryogenic) temperatures, using focused beams of electrons. Jacques Dubochet, Joachim Frank and Richard Henderson were awarded 2017 Noble Prize in Chemistry for their work in developing cryo-electron microscopy (cryo-EM).

Significance of Cryo-EM

  • Microscopes allow scientists to look at structures that cannot be seen with the naked eye – but when these structures are very tiny, it is no longer possible to use rays of light to do the job because their wavelengths are not short enough.
  • Cryo-EM technique could look at very tiny structures, but until recently, this technique could only produce fuzzy, blob-like images of biological macromolecules.
  • Instead, scientists employed methods known as x-ray crystallography and nuclear magnetic resonance (NMR) which produced fine details. However, these methods had certain drawbacks.
    • X-ray crystallography requires that proteins be crystallized before they can be scanned, but crystallization is not always possible or desirable.
    • NMR can only determine the structure of relatively small objects—certainly nothing as large as a molecular machine such as a ribosome or an ion channel.
  • But over the past several years, cryoEM has begun to produce images with the kind of near-atomic resolution that was once available only to its rivals, but without the drawbacks.
  • CryoEM can handle a wide range of scales; though the method can’t yet resolve the smallest objects available to NMR, it’s getting there, and it can already be used to image much larger ones with ease. In addition, the freezing process used in cryoEM allows proteins to remain in something resembling their native state, offering the possibility of gleaning more information about function.

Conclusion

During the recent Zika outbreak in Brazil, a group of researchers generated a high-resolution 3D image of the virus structure using Cryo-EM technique. This provided a starting point for searching for possible sites that could be targeted by drugs to prevent the spread of the virus. Understanding how biomolecules function and interact is fundamental to biochemistry, and underpins efforts to develop new drugs and medical treatments, and understand and treat diseases.

Subjects : Current Affairs