Online gamers have solved a molecular biology puzzle that may lead to new drugs to fight HIV, the virus that causes AIDS.

"This is the first instance we are aware of in which online gamers solved a long-standing scientific problem," said a blog posting on the website for Foldit, the protein folding game that tapped the gamers' skills to solve the puzzle.

"This is truly an amazing accomplishment," added another blog posting on the site. "All Foldit players should be proud."

A paper describing the solution was published online Sunday in Nature Structural & Molecular Biology. It specifically cited the contributions of gamers known by the usernames spvincent, grabhorn and mimi.

Foldit is a game released by University of Washington biochemist David Baker and his colleagues in 2009. Players compete and co-operate to find the best ways to fold a protein into a 3D structure based on the laws of physics. The shape of a folded protein is crucial to its function as a lock or key in biological processes.

The problem solved by Foldit players recently involved a protein from the virus that causes AIDS in rhesus monkeys. The protein, called a retroviral protease, has "critical roles in viral maturation and proliferation," the paper said. Researchers have been trying to figure out its shape for 15 years.

Foldit players managed to solve the puzzle in just a few days. Their solution was confirmed as the correct one by comparing the X-ray pattern it would have produced to the actual X-ray pattern produced by the protein.

"These results indi­cate the potential for integrating video games into the real-world scientific process: the ingenuity of game players is a formidable force that, if properly directed, can be used to solve a wide range of scientific problems," the paper concluded.

That resulting structure can be used in the design of antiretroviral drugs, including anti-HIV drugs, the paper said. Such drugs could bind to the protein if they are the right shape.

In particular, the protein is only active when two individual units join together, so researchers are hoping to design drugs that can prevent two units from joining.

Foldit's inventors published a paper last August showing that human Foldit players were better than computers at solving protein folding problems.

Researchers at McGill University have invented a similar game that taps video game players to find similarities between DNA sequences among different organisms that could help discover proteins important throughout evolutionary history.