With all of the medical advances in recent history, it is sometimes surprising that we have not yet found a cure for the common cold. But a new model for rhinovirus C shows unexpected structural differences, creating potential for the development of new cold drugs.

Researchers from the University of Wisconson-Madison, led by Prof. Ann Palmenberg, successfully constructed a 3D model of the cold virus, rhinovirus C, which has been called the “missing link” cold. Results of their findings, which employ the genetic sequencing of this particular cold virus to make a topographical model of the capsid – protein shell – were published recently in the journal Virology.

Though 3D structures of the A and B families of cold virus have long been known, rhinovirus C was only first discovered in 2006, when researchers discovered it had been “lurking” in human cells along with the A and B strains.

To build a model of the cold virus, Prof. Palmenberg and her team used advanced bioinformatics and the genetic sequences of 500 rhinovirus C genomes. They say these supplied the 3D “coordinates” of the viral protein shell. “The question we sought to answer was how is it different and what can we do about it? We found it is indeed quite different,” says Prof. Palmenberg. She notes that the new structure, which is significantly different from other strains of cold viruses, shows why previous drugs have failed in trials against rhinovirus. The team says the drugs that work well against the A and B strains were designed specifically to take advantage of their surface features. These structures were determined years ago using a technique called X-ray crystallography, but it could not identify the rhinovirus C structure.