Protein could be potential target for new flu drug
06 Dec 2006 22:18:28 GMT Source: Reuters
By Patricia Reaney LONDON, Dec 6 (Reuters) - Scientists said on Wednesday they have identified a weakness in a protein in influenza viruses which could be targeted by new drugs to halt the spread of infection. The protein's long tail appears to be its weak point. The tail loop is almost identical in different strains of influenza A -- the most common form of the virus. New drugs that target it could be effective against multiple strains including the feared H5N1 bird flu. "We have determined the atomic structure of the nucleoprotein from influenza A virus and found it contains a flexible tail loop," said Yizhi Jane Tao, the head of the research team from Rice University in Houston, Texas. "This protein is important for virus replication. The tail structure gives us some hints about how to design antiviral drugs by using this protein as a target," Tao explained. The scientists are now collaborating with other researchers to screen possible drug compounds that could inhibit virus replication. The findings reported in the journal Nature could pave the way for a totally new approach to tackling a virus that can be fatal. Current treatment is centred on antiviral drugs such as Roche's <ROG.VX> Tamiflu. Governments around the world have stockpiled Tamiflu against a potential flu pandemic. Some H5N1 viruses have shown resistance to the drug. Health experts fear H5N1, which has infected 258 people and killed 154 since late 2003, could mutate into a form that could become highly infectious in humans, sparking a pandemic in which millions could die. Regular seasonal influenza, type A and type B, kills between 250,000 and 500,000 people a year globally, according to the World Health Organisation. Tao and scientists at the University of Texas at Austin described the structure of the nucleoprotein (NP), which has several important functions, in the journal Nature after growing NP protein crystals on glass slides sealed inside a jar. NP is central to viral infection because after the virus has hijacked a cell, the protein forms columns that are needed for the virus to infect other cells. The tail loop of NP has about 30 amino acids, which are the building blocks of proteins. "We found that a mutation in only one residue out of 30 was enough to prevent the NPs from coming together to form the building blocks for the columns, and without these columns the virus cannot make copies and infect other cells," Tao said.
