The colorful picture to the left is an actual image of a single heart protein, a molecule that attaches cells to their surrounding environment, called metavinculin. It was obtained through a technology called cryogenic electron microscopy, or cryo-EM. The Molecular Imaging Group at The Wertheim UF Scripps Institute studies the structures of macromolecules, their complexes, cell organelles and other biological systems, through the use of advanced cryo-EM and cyrogenic electron tomography. The ability to visualize such important biological molecules including proteins, viruses and antibodies has been made possible only recently. The UF Scripps campus added this Nobel Prize-winning technology in 2020 when it purchased a cryogenic electron microscope from Jeol, the CryoARM300.
Visualizing the structures of important disease‐related molecules advances scientific knowledge and empowers scientists to custom design potential new vaccines or cancer-fighting medicines.
To visualize a biomolecule, researchers first select a screen-like grid so tiny that it requires forceps to hold. The screen is coated in a film of the molecule to be studied, and then transferred to a device called a plunge freezer that is filled with liquid nitrogen and liquid ethane. This cools the sample to hundreds of degrees below zero, so rapidly that any water molecules around it take on a glass-like, vitreous quality. The sample is then loaded into the microscope, which passes a high-brightness electron beam through it. Thousands of images are captured and then stitched together digitally to form a 3D image.
Cryo-EM at The Wertheim UF Scripps Institute
Scientists at The Wertheim UF Scripps Institute have determined the near-atomic-scale structure of an unusual brain-cell receptor called GPR158, which has been linked to depression and anxiety.
The team’s structural study reveals both the receptor and its regulating complex, advancing understanding of basic cell receptor biology. It also enables work on potential therapeutics designed to block GPR158 as a strategy for treating depression, anxiety and possibly other mood disorders.
In the study, published Nov. 18 in the journal Science, the researchers used ultracold, single-particle electron microscopy, or cryo-EM, to map, at a resolution of about a third of a billionth of a meter, the atomic structure of GPR158, both on its own and when bound to a group of proteins that mediate its activity.
“We’ve been studying this receptor for more than 10 years, and have done a lot of biology on it, so it’s really gratifying to see for the first time how it’s organized,” says lead author Kirill Martemyanov, Ph.D., Professor and Chair of the Department of Neuroscience at The Wertheim UF Scripps Institute. Read more about this discovery here.
Desmosomal Protein Under the Microscope
Some of our cells undergo constant, unrelenting stress, especially those lining blood vessels and comprising our beating hearts. What connects these active cells to each other, so that they form a functional organ or tissue? A recent study from the laboratory of Professor Tina Izard, Ph.D., illuminates the structure of one of these important proteins, plakophilin-3. It required Drs Gupta, Rangarajan, and Izard to push the boundaries to determined one of the smallest cryoEM structures reported to date by using a unique cryogenic electron microscope that the group installed recently. In collaboration with Professor Sergey Troyanovsky from Northwestern University, the scientists discovered and defined several new key interactions of plakophilin-3 that will aid the development of novel therapeutic approaches by targeting desmosomal proteins in cell adhesion and tissue integrity-related diseases. The study appears in the International Journal of Molecular Sciences.
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