Viruses invade body cells like invisible armies, and each type has its own attack strategy. But scientists are trying to resist. Many use electron microscopy, an instrument that can “see” what individual molecules in the virus do. However, even the most sophisticated technology requires the sample to be frozen and immobilized in order to obtain the highest resolution. Now physicists from the University of Utah have for the first time developed a way to visualize virus-like particles in real-time, at room temperature, with impressive resolution. The results of the study are published in the Biophysical Journal.

In a new study, the method of scientists shows that the lattice, which forms the main structural component of the human immunodeficiency virus (HIV), is dynamic. The discovery of a diffuse lattice of Gag and GagPol proteins, long considered completely static, presents new potential treatments.

When HIV particles grow from an infected cell, the viruses are delayed before they become infectious. Protease, an enzyme that is embedded as half a molecule in GagPol proteins, must bind to other similar molecules in a process called dimerization. This triggers the maturation of the virus, which leads to the appearance of infectious particles. No one knows how these semi-protease molecules find each other and dimerize, but this may be due to the rearrangement of the lattice formed by the Gag and GagPol proteins, which lie only inside the viral envelope. Gag is the main structural protein, and it has been proven that it is enough to assemble virus-like particles. Gag molecules form a lattice hexagonal structure where particles intertwine with themselves. The gaps between them are minimal. The new method showed that the Gag protein lattice is not static.

The new method is one step ahead thanks to the use of microscopy, which traditionally gives only static information. In addition to new microscopy techniques, scientists used a mathematical model and biochemical experiments to test lattice dynamics. In addition to the virus, the main consequence of the method is that researchers can see how molecules move in the cell. The study of any biomedical structure has become more accessible.

This is the first study that shows that the structure of the protein lattice of the virus in the envelope is dynamic. This new tool will be important for a better understanding of changes in the lattice as new viral particles go from immaturity to a dangerously infectious state.

What are the molecular mechanisms that lead to infection? This opens up a new line of research. If you can understand this process, perhaps you can do something so that they cannot find each other, for example, a medicine that will stop the virus.

Ipsita Saha, Postgraduate Researcher at the Department of Physics and Astronomy at the University of Utah