April 5, 2002

Electronic newsroom

Brookhaven Spotlights: News from the National Synchrotron Light Source

Seeing the Structure of the Anthrax Toxin’s Final Component

Working at the NSLS, scientists from the Boston Biomedical Research Institute and the University of Chicago’s Ben-May Institute for Cancer Research have determined the structure of anthrax’s third and last component, a protein called edema factor (EF). The structure of EF reveals the first steps of the process by which this protein inhibits the immune response of a person who has inhaled anthrax: EF binds to a protein called calmodulin – which is abundant in the host cell – prompting EF to produce chemicals that inhibit the immune response. Although the researchers do not yet have a complete understanding of how EF allows anthrax to infect host cells, this work may ultimately lead to new antibiotics.

Crystal structures of edema factor in its inactive state (left) and its calmodulin-bound active state (right). The core of edema factor (green) binds a single metal ion (purple) at the active site of both states. In the inactive state, edema factor's helical domain (yellow) is tightly associated with tuquoise and magenta loops. Calmodulin (red) activates edema factor by inserting itself between the turquoise and yellow segments, thus causing a complete rearrangement of the purple loop and prompting edema factor to produce chemicals that inhibit the body's immune response.

Reducing Sulfur Dioxide Emissions in the Air

Sulfur dioxide, a major air pollutant released by power plants, factories and cars, comes from sulfur impurities present in fossil fuels that combine with oxygen during combustion. To reduce the amount of sulfur dioxide in the air, a team of Brookhaven scientists is designing and testing compounds that take sulfur out of fossil fuels before they are processed to produce energy. The scientists found that very promising compounds made of two metals, called bimetallics, successfully remove most of the sulfur from the oil. By using x-rays and ultraviolet light produced by the NSLS, the researchers found that bimetallics made of molybdenum plus either cobalt, nickel or iron were the most efficient in removing sulfur from oil. These bimetallics have a wide range of applications for the production of environmentally friendly combustion of fuels for use in power plants, factories, houses, and transportation.

New Insight on the Origin of High-Temperature Superconductivity

A team of scientists working at the NSLS has unveiled a mechanism that may be the source of high-temperature superconductivity, which is electrical conductivity without resistance at temperatures ranging from minus 216 to minus 396 degrees Fahrenheit. Examining electrons ejected by ultraviolet light from these materials, the scientists found that superconductivity might arise when the magnetic fields of electrons and neighboring atoms interact with each other. This process brings new insight to the origin of high-temperature superconductivity, a phenomenon that is still not well understood. It is thought to be different from the mechanism in low-temperature superconductors, in which superconductivity is thought to arise from pairs of electrons exchanging vibrations with the surrounding crystal lattice.

A Shortcut For Examining Protein Structures

Scientists from Los Alamos National Laboratory working at the NSLS are pioneering a new use of x-ray powder diffraction, a well-known technique to determine the structure of large proteins faster than ever before. This technique is based on x-ray diffraction, which consists of looking at the way x-rays scatter off a crystal to determine its structure. To study large proteins using x-rays, scientists usually grow one large crystal of a protein made of hundreds of thousands of atoms — a task that requires weeks of intense work. Instead, the Los Alamos scientists prepared a powder made of numerous very small crystals of a protein, a process that takes only a few seconds. They used this method to examine the structures of large proteins, such as complexes involving lysozyme — an antibacterial protein — and a new form of insulin. This method shows great promise for wide application in the pharmaceutical industry.

A Major Milestone Toward Producing Intense Ultraviolet Synchrotron Light

NSLS scientists are developing a new light source, called the Deep Ultra-Violet Free Electron Laser (DUV-FEL), that is expected to produce light pulses up to 1,000 times shorter and a billion times more intense than light from the NSLS. The ultimate goal of the DUV-FEL is to generate light at wavelengths shorter than 100 nanometers (vacuum ultra-violet light), which may open up new areas of research, just as the NSLS did when it began operating 20 years ago. The effort to design and build the DUV-FEL started in 1995, and has recently led to an important milestone: production of 400-nanometer-wavelength light (visible blue light) by a process known as self-amplified spontaneous emission, demonstrating that the components of the machine are working properly. With this result in hand, the scientists are confident that the goal of 100 nanometers is within reach.