Interesting tech developments in nanotech, nanostructured materials, etc.
Ken Novak's Weblog
Thursday, February 26, 2004
Marine sponges provide model for nanoscale materials production: "[Dan] Morse directs the new Institute for Collaborative Biotechnologies, a UCSB-led initiative funded by a grant of $50 million from the Army Research Office, which operates in partnership with MIT and Caltech. .. his research group discovered that the center of the sponge's fine glass needles contains a filament of protein that controls the synthesis of the needles. By cloning and sequencing the DNA of the gene that codes for this protein, they discovered that the protein is an enzyme that acts as a catalyst, a surprising discovery. Never before had a protein been found to serve as a catalyst to promote chemical reactions to form the glass or a rock-like material of a biomineral. From that discovery, the research group learned that this enzyme actively promotes the formation of the glass while simultaneously serving as a template to guide the shape of the growing mineral (glass) that it produces ..
"we've discovered that these activities can be applied to the synthesis of valuable semiconductors, metal oxides such as titanium and gallium that have photovoltaic and semiconductor properties," says Morse. The group is using a synthetic mimic of the enzymes found in marine sponges. These discoveries are significant because they represent a low temperature, biotechnological, catalytic route to the nanostructural fabrication of valuable materials 12:56:31 AM
Wednesday, February 18, 2004
Seeing how plants split water: "Reporting online in the journal Science today Imperial researchers reveal the fine detail of the protein complex that drives photosynthesis..
Photosynthesis occurs in plants, some bacteria and algae and involves two protein complexes, photosystem I, and photosystem II - which contains the water-splitting center. While previous models of PSII function have sketched out a picture of how the water splitting center might be organized, the Imperial team were able to reveal the structure of the centre at a resolution of 3.5 angstroms (or one hundred millionth of a centimetre) in the cyanobacterium, Thermosynechococcus elongatus by combining the expertise of Professor So Iwata in solving protein structures and Professor Jim Barber in the photosynthetic process.
"Results by other groups, including those obtained using lower resolution X-ray crystallography at 3.7 angstroms have shown that the splitting of water occurs at a catalytic center that consists of four manganese atoms (Mn)," explains Professor So Iwata of Imperial's Department of Biological Sciences. "We've taken this further by showing that three of the manganese atoms, a calcium atom and four oxygen atoms form a cube like structure, which brings stability to the catalytic center. The forth and most reactive manganese atom is attached to one of the oxygen atoms of the cube. Together this arrangement gives strong hints about the water-splitting chemistry.
"Our structure also reveals the position of key amino acids, the building blocks of proteins, which provide a details of how cofactors are recruited into the reaction centre," Barber said. "PSII is truly the 'engine of life' and it has been a major challenge of modern science to understand how it works. Manufacturing hydrogen from water using the photosynthetic method would be far more efficient than using electrolysis" 9:01:44 AM