Could a drug engineered from bananas fight many deadly viruses?

A banana a day may not keep the doctor away, but a substance originally found in bananas and carefully edited by scientists could someday fight off a wide range of viruses, new research suggests.

And the process used to create the virus-fighting form may help scientists develop even more drugs, by harnessing the "sugar code" that our cells use to communicate. That code gets hijacked by viruses and other invaders.

The new research focuses on a protein called banana lectin, or BanLec, that "reads" the sugars on the outside of both viruses and cells. Five years ago, scientists showed it could keep the virus that causes AIDS from getting into cells -- but it also caused side effects that limited its potential use.

Now, in a new paper published in the journal Cell, an international team of scientists reports how they created a new form of BanLec that still fights viruses in mice, but doesn't have a property that causes irritation and unwanted inflammation.

They succeeded in peeling apart these two functions by carefully studying the molecule in many ways, and pinpointing the tiny part that triggered side effects. Then, they engineered a new version of BanLec, called H84T, by slightly changing the gene that acts as the instruction manual for building it.

The result: a form of BanLec that worked against the viruses that cause AIDS, hepatitis C and influenza in tests in tissue and blood samples -- without causing inflammation. The researchers also showed that H84T BanLec protected mice from getting infected by flu virus.