Installation of a Thermo Scientific Talos Arctica 200 Kv cryo-transmission electron microscope (cryo-TEM) is nearly complete in the Glaxo Research Building at the University of North Carolina at Chapel Hill. Once functioning this summer, this $3-million instrument will bring exciting new capabilities to researchers across the university and others in the RTP area. The Talos Artica will be the centerpiece of the new cryoEM core facility, directed by Joshua Strauss, PhD, a research assistant professor in the department of biochemistry and biophysics. It will provide researchers with assistance in all aspects of cryoelectron microscopy (cryoEM) to include specimen preparation, data acquisition, and image analysis.
CryoEM is a 3-dimensional imaging method that uses a transmission electron microsope (TEM) to visualize biological samples in a frozen hydrated near-native state.
“CryoEM is revolutionizing biology and has broad applicability to many fields in the biomedical sciences. We are very excited to bring this technology to UNC,” said Blossom Damania, PhD, Vice Dean for Research in the School of Medicine.
Strauss said, “This method can be used to study a wide range of biological samples including purified macromolecules, viruses, and cellular components. There are different approaches to generate a 3-dimensional structure from cryo-TEM, such as tomography and sub-volume averaging, electron diffraction, helical based reconstruction, etc. The most common approach is single-particle cryoEM.”
Single-particle cryoEM involves taking thousands and sometimes millions of images of molecules embedded in a thin film of ice with the TEM, then using computational approaches to classify and average these images into a 3D volume.
Cryoelectron microscopy has existed for more than 30 years. But prior to 2011, single-particle cryoEM was mainly used for examination of large macromolecular complexes. Within the past eight years, technological advances in instrumentation and image processing algorithms have enabled researchers to 3-D visualize macromolecular complexes of a variety of sizes with near-atomic to atomic resolution.
There has been a huge surge of interest in cryoEM within the structural biology community, Strauss said. Many biologists are now using this method to study protein structures that aren’t as amenable to other experimental techniques, such as X-ray crystallography or nuclear magnetic resonance (NMR).
“CryoEM has profound implications for basic biomedical science research and our understanding of macromolecular structures,” Strauss said. “Several applications have a direct impact on human health and medicine.”
Complexes of proteins, RNA, DNA, and drugs are now being examined at levels of resolution that will make it possible to design higher affinity drugs for the treatment of cancers and many other diseases. Atomic models of human proteins associated with genetic disorders will provide new structural information that researchers can use to gain a deeper understanding of the molecular basis of human diseases and the development of more accurate molecular diagnostical approaches.
Structural determination of viruses and viral proteins in the presence of neutralizing antibodies or molecular inhibitors have been used for drug and vaccine development.
“As cryoEM is still an evolving technology, we can expect different areas of structural and cellular biological to be explored using this technique,” Strauss said.
Momentum to bring cryo-EM to the Triangle region of North Carolina began four years ago with an effort from School of Medicine faculty at the UNC Lineberger Comprehensive Cancer Center and the department of biochemistry and biophysics. Leaders and researchers, including Leslie Parise, PhD., at the UNC School of Medicine focused attention on the need for this technology in the Triangle area of North Carolina. Acknowledging this, the National Institute of Environmental Health Sciences (NIEHS) in Research Triangle Park (RTP) acquired a Talos Arctica TEM which was installed this past year.
In parallel, Duke University purchased and installed a 300 Kv Titan Krios TEM instrument also produced by Thermo Fisher Scientific. Image collection with this cryo-TEM has just begun.
The Talos Arctica purchased by UNC-Chapel Hill is equipped with a Gatan K3 direct-electron detector camera – the newest electron detector camera – and it will provide unique capabilities.
NIEHS, Duke University, and UNC-Chapel Hill are part of a collaborative group – the molecular microscopy consortium – directed by Mario Borgnia, PhD, at the NIEHS, which is committed to development of CryoEM for the greater RTP area. The UNC Talos Artic has been delivered and installed, and it is expected to be ready for research groups by this summer.
Story courtesy of Mark Derewicz, UNC Healthcare Communications