U.S. scientists have created the first 3D map of the part of the new coronavirus that attaches to and infects human cells, a critical step toward developing vaccines and treatments.

The team from the University of Texas at Austin and the National Institutes of Health studied the virus’s genetic code, which had made publicly available by Chinese researchers, and used it to develop a stabilized sample of a key part called the spike protein.

They then imaged the spike protein using cutting-edge technology known as cryogenic electron microscopy, publishing their findings in the journal Science on Wednesday.

“The spike is really the antigen that we want to introduce into humans to prime their immune response to make antibodies against this so that when they then see the actual virus, their immune systems are ready and loaded to attack,” said UT Austin scientist Jason McLellan, who led the research.

He added that he and his colleagues had already spent many years studying other members of the coronavirus family, including SARS and MERS, which helped them develop the engineering methods required to keep the spike protein stable.

Their engineered spike protein is itself being tested as a potential vaccine by the NIH.

The team is sending the map of its molecular structure out to collaborators around the world so they can improve it by making it provoke a greater immune response.

The model can also help scientists develop new proteins to bind to different parts of the spike and prevent it from functioning, to treat those already infected. These proteins are known as antivirals.

“This is a beautifully clear structure of one of the most important coronavirus proteins — a real breakthrough in terms of understanding how this coronavirus finds and enters cells,” said virologist Benjamin Neuman at the Texas A&M University-Texarkana, who was not involved in the work. “The structure shows that although the spike is made of the three identical proteins, one flexes out above the rest, effectively giving the virus a longer reach.”

A useful aspect of the structure for vaccine development is that it maps out the size and location of chains of sugar molecules that the virus uses in part to avoid being detected by the human immune system, added Neuman.

Cryogenic electron microscopy uses beams of electrons to examine the atomic structures of biomolecules that are frozen to help preserve them.

Three scientists credited with developing the technology were awarded the 2017 Nobel Prize in chemistry.

RELATED PHOTOS A 3D atomic scale map, or molecular structure, of the 2019-nCoV spike protein is seen Wednesday. U.S. scientists announced they had created the first 3D atomic scale map of the part of the novel coronavirus that attaches to and infects human cells, a critical step toward developing vaccine and treatments. | JASON MCLELLAN / UNIVERSITY OF TEXAS AT AUSTIN / VIA AFP-JIJI