Proteins are the doers of biology. In the human body, they do most of the work in cells and are necessary for the structure, function, and regulation of the body’s tissues and organs. Each protein is made of a precise sequence of amino acids that allows it to fold into a three-dimensional shape that determines its function. In the past, the all-important structure of a protein could only be established through difficult and time-consuming laboratory analyses. Now comes a dramatic new twist – a window into the fundamental building blocks of life.