With the Zika virus outbreak still ongoing in Latin America, the race is on to find a vaccine. Now, researchers at Purdue University in the US have determined the virus’s structure, which could provide crucial insights into how the virus works.
The current outbreak of the mosquito-borne Zika virus began in Brazil in April 2015, and has since spread to other countries across South America, Central America, Mexico, and the Caribbean. In pregnant mothers, the virus has been linked to microcephaly, a birth defect that causes brain damage and an abnormally small head in newborn babies. In February, this was declared by the WHO as a ‘Public Health Emergency of International Concern’.
To unravel the structure of the virus, the team used a technique called ‘cryo-electron microscopy’. This uses a beam of electrons to study the sample at extremely low temperatures.
“Since the 1950s, X-ray crystallography has been the standard method for determining the structure of viruses, but it requires a relatively large amount of virus, which isn’t always available,” says Michael Rossmann at Purdue University. “Now, we can do it through electron microscopy and view the virus in a more native state. This was unthinkable only a few years ago.”
The researchers found subtle structural differences in the virus compared to other flaviviruses – the family to which the Zika virus belongs, which also includes the West Nile, dengue and yellow fever viruses. The team focused on a region in the virus’s shell known as a ‘glycosylation site’, which might be involved in the virus’s attachment to human cells.
“If this site functions as it does in dengue and is involved in attachment to human cells, it could be a good spot to target an antiviral compound,” says Rossman. The search for a vaccine continues…