Creating a New View
The NRAMM group, led by Scripps Research Associate Professors Clinton Potter and Bridget Carragher and working with Scripps Research Kellogg School of Science and Technology graduate students Anke Mulder and Craig Yoshioka, developed a new technique, described in the Science paper and dubbed discovery single-particle profiling, which dodges the purification problem by allowing successful imaging of unpurified samples. An automated data capture and processing system of the team's design enables them to decipher an otherwise impossibly complex hodgepodge of data that results.
For this project, second author Andrea Beck, a research assistant in the Williamson laboratory, purified ribosome components from cells of the common research bacterium Escherichia Coli. She then chemically broke these apart to create a solution of the components that form ribosomes. The components were mixed together and then were rapidly stained and imaged using electron microscopy. "We went in with 'dirty' samples that contained horribly complex mixtures of all different particles," said Williamson.
Mulder, who is first author on the paper, collected and analyzed the particles that were formed during the ribosome assembly reaction. Using the team's advanced algorithms, they were able to process more than a million data points from the electron microscope to ultimately produce molecular pictures.
The Pieces Fit
The team produced images that the scientists were able to match like puzzle pieces to parts of ribosomes, offering strong confirmation that they had indeed imaged and identified actual chemical intermediates in the path to ribosome production. "We always saw the same thing no matter how we processed the data, and this led us to believe this was real," said Williamson.
|Contact: Mika Ono|
Scripps Research Institute