Proteins are the workhorses of our cells: They turn food into energy and determine our health. Each one is a chain of molecules—sometimes thousands of links long—that folds in a distinctive way. Understanding how they fold can help scientists block diseases, but there are so many variables involved that even powerful computers struggle to do it.
Enter Zoran Popović. The Serbian computer scientist emigrated to the U.S. in the late 1980s and got a scholarship to Brown University. He knew so little about the school he thought he’d be studying on an island off the coast of Massachusetts called “Rhodes.” In 2000 the University of Washington hired him to teach computer science, and he earned a reputation for pushing the state-of-the-art in gaming graphics.
Three years ago he met David Baker, a biochemistry professor struggling with the problem of protein folding. Together they came up with Foldit. It’s an online game that invites anyone to solve the mysteries of protein-folding in a slick, Tetris-like interface. Proteins fold according to rules of physics: They follow the path of least resistance, opposite charges attract, and the bonds between atoms have limited angles of rotation. In the game, players click and drag parts of a protein and rack up points as they grope toward the most energy-dense, compact way to fold them. Behind the scenes, computers run through biochemistry equations to determine players’ scores. “We ended up using both computers and people in a symbiosis,” Popović says.
Since Foldit launched in 2008, it has attracted hundreds of thousands of gamers. Most, like Popović, have little or no training in biochemistry. The first breakthrough came in 2010, when players managed to decipher the structure of a protein crucial to the replication of the AIDS virus. “The very first reaction was disbelief,” says Mariusz Jaskólski, a Polish scientist who worked on that particular protein structure for years and says the Foldit discovery has given him a new target for designing drugs.
Popović became the head of the Center for Game Science at UW in 2010 and has spent his time since then expanding his game library. Foldit now allows players to design proteins that don’t exist in nature, potentially creating ones that behave in novel ways. In August, Popović will unveil a game that will teach players to build tiny machines made out of DNA. Popović says players will be able to create structures that can sniff out and eliminate cancer cells while leaving healthy cells intact. “Turns out DNA structure can do things nature hasn’t thought of yet,” he says. Another game in the works will turn players into investigative journalists.
In all his games, Popović pays close attention to player feedback. With Foldit, he added a “cookbook” that allows gamers to reuse bits of programming, a commonly requested feature. “We didn’t design a game and it was good,” says Popović. “We designed a game that wasn’t good, and we continuously improved it.”