Berkeley Scientists Find that a Critical Transcription Factor Co-exists in Two Distinct States
The enormously diverse complexity seen amongst individual species within the animal kingdom evolved from a surprisingly small gene pool. For example, mice effectively serve as medical research models because humans and mice share 80-percent of the same protein-coding genes. The key to morphological and behavioral complexity, a growing body of scientific evidence suggests, is the regulation of gene expression by a family of DNA-binding proteins called “transcription factors.” Now, a team of researchers with the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley has discovered the secret behind how one these critical transcription factors is able to perform – a split personality. (more…)
The first detailed and complete picture of a protein complex that is tied to human birth defects as well as the progression of many forms of cancer has been obtained by an international team of researchers led by scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab). Knowing the architecture of this protein, PRC2, for Polycomb Repressive Complex 2, should be a boon to its future use in the development of new and improved therapeutic drugs.
“We present a complete molecular organization of human PRC2 that offers an invaluable structural context for understanding all of the previous biochemical and functional data that has been collected on this complex,” says Berkeley Lab biophysicist Eva Nogales, an electron microscopy expert who led this research. “Our model should also be an invaluable tool for the design of new experiments aimed at asking detailed questions about the mechanisms that enable PRC2 to function and how those mechanisms might be exploited.” (more…)
Berkeley Lab and SLAC Researchers Study Key Protein Complex Crucial to Photosynthesis
Future prospects for clean, green, renewable energy may hinge upon our ability to mimic and improve upon photosynthesis – the process by which green plants, algae and some bacteria convert solar energy into electrochemical energy. An artificial version of photosynthesis, for example, could use sunlight to produce liquid fuels from nothing more than carbon dioxide and water. First, however, scientists need a better understanding of how a large complex of proteins, called photosystem II, is able to split water molecules into oxygen, electrons and hydrogen ions (protons). A new road to reaching this understanding has now been opened by an international team of researchers, led by scientists at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and SLAC National Accelerator Laboratory.
Using ultrafast, intensely bright pulses of X-rays from SLAC’s Linac Coherent Light Source (LCLS), the research team produced the first ever images at room temperature of microcrystals of the photosystem II complex. Previous imaging studies, using X-rays generated via synchrotron radiation sources, required cryogenic freezing, which alters the samples. Also, to catalyze its reactions, photosystem II relies upon an enzyme that contains a manganese-calcium cluster that is highly sensitive to radiation. With the high-intensity femtosecond X-ray pulses of the LCLS, the research team was able to record intact images of these clusters before the radiation destroyed them. (more…)
