Zika Structure Map Could Stem Virus’ Spread

     (CN) – Scientists from Purdue University said Thursday they have discovered the structure of the Zika virus, which could lead to methods for stemming the spread of the mosquito-borne virus.
     Zika, which has swept through at least 30 nations in Latin America and the Caribbean, is linked to microcephaly and Guillain-Barre syndrome, along with other potential birth defects.
     The researchers were able to map Zika’s physical structure to a near-atomic level, which will assist experts in developing vaccines, antiviral treatments, and strategies to stop the virus’ spread locally. Zika has been difficult to thwart partially due to the lack of scientific knowledge about the virus.
     “Determining the structure greatly advances our understanding of Zika – a virus about which little is known. It illuminates the most promising areas for further testing and research to combat infection,” study co-leader Dr. Richard Kuhn said in a statement.
     Kuhn and co-author Dr. Michael Rossmann were the first researchers to map the structure of a flavivirus – dengue – in 2002. The pair then determined the structure of the West Nile virus in 2003.
     The study confirmed that Zika’s structure is very similar to other flaviviruses, a family of mosquito-borne illnesses such as dengue, yellow fever and West Nile, with the exception of one protein.
     Kuhn’s team, using an electron microscope, discovered that all known flavivirus structures differ in the amino acids that surround a glycosylation site, which helps proteins fold properly in order to form structures. The glycosylation site is in the virus shell, which is made up of 180 copies of two different proteins – each composed of chains of different amino acids.
     Genetic information in the form of RNA is surrounded by a fatty membrane and encased in a protein shell with a 20-sided face.
     Upon entering a target cell, the virus spreads and forces the host to change by replacing instructions coded in its DNA with what is programmed by the viral RNA.
     Zika differs at the glycosylation site in that it actually protrudes from the virus’ shell, which is thought to be crucial to cellular break-in. This protrusion is similar to the dynamic of a stranger offering a child candy, and tricks the human cell into binding with the invader.
     “Most viruses don’t invade the nervous system or the developing fetus due to blood-brain and placental barriers, but the association with improper brain development in fetuses suggest Zika does,” Devika Sirohi, a graduate student and co-leader of the study, said. “It is not clear how Zika gains access to these cells and infects them, but these areas of structural difference may be involved. These unique areas may be crucial and warrant further investigation.”
     Additional research into how Zika is able to penetrate the nervous system and barriers protecting fetuses could provide significant assistance in steering research efforts to develop vaccines and tests.
     “The structure of the virus provides a map that shows potential regions of the virus that could be targeted by a therapeutic treatment, used to create an effective vaccine or to improve our ability to diagnose and distinguish Zika infection from other related viruses,” Kuhn said.

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