Our bodies make roughly 20,000 different kinds of proteins, from the collagen in our skin to the hemoglobin in our blood. Some take the shape of molecular sheets. Others are sculpted into fibers, boxes, tunnels, even scissors.

A protein’s particular shape enables it to do a particular job, whether ferrying oxygen through the body or helping to digest food.

Scientists have studied proteins for nearly two centuries, and over that time they’ve worked out how cells create them from simple building blocks. They have long dreamed of assembling those elements into new proteins not found in nature.

But they’ve been stumped by one great mystery: how the building blocks in a protein take their final shape. David Baker, 55, the director of the Institute for Protein Design at the University of Washington, has been investigating that enigma for a quarter-century.