Scientists from Caltech have solved the crystal structure of an ATP-binding Cassette (ABC) transporter called HI1470/1 from the bacteria Haemophilus influenzae. This particular transporter, which is a member of a large family of related proteins prevalent in most organisms including humans, is responsible for moving nutrients across cell membranes. The structure of HI1470/1 exhibits an alternate conformation to that previously observed for the related transporter BtuCD, such that their pathways for moving nutrients open to opposite sides of the membrane. These results give scientists a look at both the beginning and ending stages of how proteins transport nutrients across the membrane bilayers that surround all cells.
Approximately 1,600 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 and to add your most recent publications to this collection.
While we continue to refine our science highlights content you may access older science summaries that date between 04/2001 to 06/2010 by visiting http://www-ssrl.slac.stanford.edu/science/sciencehighlights.html. We will be offering science summaries that date from 06/2012 to the present soon.
May 2007
X-ray diffraction
BL9-2
April 2007
Researchers from the University of California, Santa Cruz, using macromolecular crystallography beam line 9-1 at SSRL have determined the three-dimensional structure of an RNA enzyme, or "ribozyme," that carries out a fundamental reaction required to make new RNA molecules. Their results provide insight into what may have been the first self-replicating molecule to arise billions of years ago on the evolutionary path toward the emergence of life. The findings are published in the March 16 issue of the journal Science.
Macromolecular Crystallography
BL9-1
April 2007
A team of researchers working at SSRL has determined the atomic structure of an assemblage of fiber-forming proteins found in the cell membranes of many dangerous types of bacteria. The protein, called pilin, assembles into filamentous organelles called Type IV pili found on the surfaces of most Gram-negative bacteria. Type IV pili plays a central role in how these bacterial pathogens infect a host and are involved in cellular functions such as motility, adhesion, microcolony formation and uptake of DNA and specific filamentous phage.
Macromolecular Crystallography
BL7-1, BL9-1, BL9-2, BL11-1
March 2007
In 1974, while sinking irrigation wells in the Chinese province of Shaanxi, a group of farmers made an astonishing archeological discovery. Buried beneath their feet stood a contingent of 8,000 life-sized terra cotta warriors and their horses, facing east, ready for battle. The figures, later found to be more than 2,000 years old, were accompanied by weapons, real chariots, and objects of jade and bone. It was later determined that this army was built to protect the tomb of the first emperor of the Qin dynasty, Shi Huang Di.
March 2007
Botulinum neurotoxin is produced by the bacteria Clostridium botulinum and is the most potent toxin known, inducing a potentially fatal paralysis known as "botulism." Botulism can occur in a number of ways, including infection through open wounds or in the intestinal tract, or after consuming contaminated food in which toxin has been produced. In the USA, infant botulism is the most common manifestation of the disease-some speculate whether its prevalence is linked to sudden infant death syndrome. On the other hand, these neurotoxins have also become a powerful therapeutic tool for treating a variety of neurological, ophthalmic, and other disorders manifested by abnormal, excessive, or inappropriate muscle contractions.
X-ray diffraction
BL9-1
March 2007
Botulinum neurotoxin is produced by the bacteria Clostridium botulinum and is the most potent toxin known, inducing a potentially fatal paralysis known as "botulism." Botulism can occur in a number of ways, including infection through open wounds or in the intestinal tract, or after consuming contaminated food in which toxin has been produced. In the USA, infant botulism is the most common manifestation of the disease-some speculate whether its prevalence is linked to sudden infant death syndrome. On the other hand, these neurotoxins have also become a powerful therapeutic tool for treating a variety of neurological, ophthalmic, and other disorders manifested by abnormal, excessive, or inappropriate muscle contractions.
February 2007
In a recent experiment performed at SLAC and reported in the February 2 issue of Science, David Fritz and his SPPS colleagues have obtained our first direct view of the motion of atoms inside a crystal. This feat requires simultaneous Angstrom spatial and femtosecond temporal resolution. Synchrotrons have been providing subatomic resolution for decades, and ultrafast lasers have been capable of sub-picosecond timing for more than twenty years; but SPPS was the first instrument to combine both.
February 2007
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
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.
A New Slant on a Cellular Balancing Act — the Copper-sensing Repressor of Mycobacterium tuberculosis
January 2007
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
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