125 Stanford Stories

NO. 6
Firsts

Molecular movies

New drug therapies are just one potential outcome of a SLAC imaging tool that captures chemical changes at atomic scale.

SLAC’s “molecular movies” reveal the smallest processes of life

What is a femtosecond? It’s a million-billionth of a second, a timescale largely theoretical until the SLAC National Accelerator Laboratory at Stanford developed a tool in 2009 that takes million-billionth-of-a-second snapshots of changes within molecules, the smallest activity known.

The brightness of SLAC’s Linac Coherent Light Source (LCLS) allows it to produce uniquely fast X-ray laser exposures, just one femtosecond long. Spliced together, these images form “molecular movies” that depict chemical changes at previously unobtainable scale, revealing fundamental processes in materials, technology and living things.

LCLS has found immediate and global application in pharmaceutical research. Scientists from around the world come to LCLS to observe the atomic processes at work when various drugs interact with cells. Already, LCLS has enabled scientists to uncover the 3-D molecular structure of an enzyme involved in the transmission of African sleeping sickness and to to study how a new type of painkiller with potentially reduced side effects interacts with a specialized protein that regulates the body’s pain response. Recently, LCLS took the world’s first X-ray portraits of living bacteria, a first step toward explorations of the molecular machinery at work in viral infections, cell division and photosynthesis.