(Photo: VCG)

WASHINGTON, Feb. 17 (Xinhua) -- Scientists in the United States for the first time mapped the 3D atomic structure of a family of viruses including measles, mumps and flu.

The study published on Monday in the Proceedings of the National Academy of Sciences described the 3D atomic structure of a key enzyme complex in paramyxoviruses. The findings could help design and develop antiviral drugs for those viruses and coronavirus, which functions similarly to paramyxoviruses.

Northwestern University researchers used cryogenic electron microscopy to peer inside molecules to determine the 3D shape of proteins, which are often thousands of times smaller than the width of a human hair.

"This takes some of the guesswork out of designing drugs," said Robert Lamb, Professor of Molecular Biosciences at Northwestern. "Traditionally, you have to develop drugs randomly and hope you hit a target, but it doesn't happen very often."

They captured hundreds of thousands of images of one sample of human parainfluenza virus 5 polymerase, and then used computational algorithms to reconstruct a 3D image.

The resulting image was an irregular, round-shaped globule with a long tail made of four proteins containing phosphorus and the structure contains more than 2,000 amino acids and five proteins, according to the study.

The team has found that this virus uses the same protein to switch between genome replication and transcription.

"It gets both jobs done with one enzyme. The virus's genome is so small, and this gives it economy of scale," said Lamb.