SSRL Science Highlights Archive

Approximately 1,700 scientists visit SSRL annually to conduct experiments in broad disciplines including life sciences, materials, environmental science, and accelerator physics. Science highlights featured here and in our monthly newsletter, Headlines, increase the visibility of user science as well as the important contribution of SSRL in facilitating basic and applied scientific research. Many of these scientific highlights have been included in reports to funding agencies and have been picked up by other media. Users are strongly encouraged to contact us when exciting results are about to be published. We can work with users and the SLAC Office of Communication to develop the story and to communicate user research findings to a much broader audience. Visit SSRL Publications for a list of the hundreds of SSRL-related scientific papers published annually. Contact us to add your most recent publications to this collection.

SCIENCE HIGHLIGHT BANNER IMAGES

February 2007
Figure 1.

The FeFe-hydrogenases are of great interest because they can catalyze both the forward and reversed dihydrogen uptake/evolution reactions. Under optimal conditions a single molecule of FeFe-hydrogenase can produce approximately 9000 molecules of hydrogen per second. This translates into a theoretical capacity for refueling the hydrogen tank of the Space Shuttle within 30 minutes. Thus, hydrogenases are considered as desirable biological targets for hydrogen-based energy production and utilization technologies.

X-ray Absorption Spectroscopy
BL6-2
February 2007
W. F. Schlotter
Figure 1.

Scientists at SSRL have demonstrated a novel approach for improving the efficiency of an x-ray microscopy technique that may in particular prove beneficial for imaging radiation-sensitive objects such as biological samples. The findings, published in the October 2006 issue of Applied Physics Letters, should enhance imaging of sensitive samples and improve imaging with future ultra-short pulsed light sources, such as the Linac Coherent Light Source.

January 2007
W.G.J. Hol, J. Bosch
Figure 1.

Researchers from the University of Washington working at SSRL have solved the structure of a protein complex that may one day be exploited to combat drug-resistant strands of the parasite that causes malaria, Plasmodium. Malaria, one of the most devastating diseases worldwide, infects 300 to 500 million people and causes about 2 million deaths each year.

Macromolecular Crystallography
BL9-2
January 2007
Figure 1.

Scientists have discovered a gene for a protein that regulates the cellular response to copper in the bacterium that causes tuberculosis. These findings, reported in the January issue of Nature Chemical Biology, explain how a wide variety of bacteria control copper concentrations within their cells, and this understanding could lead to new treatments for tuberculosis.

X-ray Absorption Spectroscopy
BL9-3
January 2007
Z.-X. Shen, K. Tanaka, D.H. Lu
Figure 1.

Scientists at Stanford University have recently made an important discovery about the coexistence of two distinct energy gaps in photoemission spectra of high temperature superconductors. The two gaps have opposite doping dependence, which provides an explanation for the contradictory results about the superconducting gap deduced from different experimental techniques. The findings, published in the December 22 issue of Science, have profound implications for the mechanism of high temperature superconductivity.

Angle-resolved photoelectron spectroscopy
BL5-4
December 2006
Wang, D., Bushnell, D.A., Kornberg, R.D.
Figure 1.

Life as we know it depends on turning on and off the proper genes at the correct time. This process of gene expression starts when an RNA message is copied from DNA. Scientists have long known that an enzyme called RNA polymerase II plays the central role in this delicate transcription process. But the exact mechanism by which RNA polymerase II selects specific nucleotides and catalyzes the reaction that incorporates them into a growing RNA strand has not been well understood.

Macromolecular Crystallography
BL9-2, BL11-1
December 2006
Piero Pianetta, Stanford Synchrotron Radiation Lightsource
Figure 1.

An international collaboration that included researchers at SSRL has used x-ray scanning microprobe fluorescence techniques at BL6-2 to characterize the elemental chemistry of samples from comet 81P/Wild-2 brought back aboard the Stardust spacecraft last January. Twenty-three aerogel samples containing cometary particles were analyzed by the 175-member Preliminary Examination Team, and five of those samples were studied at SSRL. This collaboration provided the first look at the Stardust samples after the return, and results are presented in several publications in the December 15 issue of Science.

X-ray Absorption Spectroscopy
BL6-2
December 2006
Mathews, I. I., Khosla, C., Tang, Y., Cane, D. E.
Figure 1.

Researchers have obtained the highest-resolution image of a didomain structure in a modular polyketide synthase (PKS), revealing new structural features. PKS enzymes catalyze the synthesis of polyketides, which include a number of antibiotics, anticancer agents, antiparasitics, and immunosuppressants. The researchers solved the x-ray crystal structure of a didomain of 6-deoxyerythronolide B synthase (DEBS), a model PKS using data measured at SSRL Structural Molecular Biology Beam Line 11-1. They imaged a 194-kDA fragment of module 5 of the enzyme with multiwavelength anomalous dispersion (MAD).

Macromolecular Crystallography
BL11-1
November 2006
J. Yano, V. Yachandra
Figure 1.

Billions of years ago, primitive bacteria developed a way to harness sunlight to split water molecules into protons, electrons and oxygen-the cornerstone of photosynthesis. Now, a team of scientists has taken a major step toward understanding this process by deriving the precise structure of the catalytic metal-cluster center containing four manganese atoms and one calcium atom (Mn4Ca) that drives this water-splitting reaction. This catalytic center resides in a large protein complex, called photosystem II, found in plants, green algae, and cyanobacteria. The international team was led by scientists from LBNL, and includes scientists from Germany's Technical and Free Universities in Berlin, the Max Planck Institute in Mülheim, and from SSRL.

X-ray Absorption Spectroscopy
BL9-3
November 2006
Garcia, K.C., Milbrandt, J., Wang, X., Baloh, R.H.
Figure 1.

Researchers have for the first time obtained a high-resolution structure of a three-molecule receptor-ligand complex that could help shed light on neurodegenerative diseases such as Parkinson's. The complex includes two receptor molecules, called GFRα3, bound with its ligand, artemin, which fit together like a lock and key. These molecules play a key role in chemical signal transmission and in the development and health of neurons.

Macromolecular Crystallography
BL11-1

Pages

Subscribe to SSRL Science Highlights
Find Stanford Synchrotron Radiation Lightsource on TwitterFind Stanford Synchrotron Radiation Lightsource on YouTubeFind Stanford Synchrotron Radiation Lightsource on Flickr