ChemWeb Newsletter

Not a subscriber? Join now.October 10, 2006


This week The Alchemist learns of RNA revelations earn a Nobel Prize, finds out how to get wood and plastic to combine more effectively using a polymer compatibilizer, and discovered that a couple of scrambled pentagons can lead to egg-shaped buckyballs. Also in this week's issue water works as an electrical conductor at a much lower temperature and pressure than previously suggested, which could explain the planet Neptune's magnetic field. Finally, an anticoagulant drug with a built-in antidote.

Stanford University's Roger Kornberg has picked up this year's Nobel Prize for Chemistry for his pioneering X-ray crystallographic work that revealed for the first time in atomic detail how the genetic code held in DNA is transcribed into messenger RNA and so used for protein production in the cells of all eukaryotes from yeast to yak by way of human beings. His RNA revelations have implications for understanding and treating cancer, heart disease, poisoning, and the development of stem cells in medicine. Transcription is necessary for all life. This makes the detailed description of the mechanism that Roger Kornberg provides exactly the kind of "most important chemical discovery" referred to by Alfred Nobel in his will. Roger Kornberg's father Arthur won the 1959 Nobel Prize for Medicine for his work on DNA. This year's award makes the Kornbergs the sixth father and son to win a Nobel. The Nobel Prize for Medicine this year was awarded to Stanford's Andrew Fire and Craig Mello of University of Massachusetts Medical School for their work on RNA interference and gene silencing, the counterpoint to gene expression described by Kornberg.

Researchers in the College of Forestry at Oregon State University have created an entirely new composite material based on wood and plastic. The new material is stronger and less expensive to manufacture than other products currently available and represents something of a breakthrough for this "growing" industry. Wood-plastic composites, are commonly used in outdoor domestic settings for outdoor decking and other such implementations. "Composite products made from wood and plastic are highly desirable for their low maintenance and ability to resist rot," explains OSU's Kaichang Li, "But their use has been limited because of high cost and low strength, a result of inadequate adhesion between the wood fibers and plastic." Wood and plastic do not form a natural bond, but Li and his colleagues have created what they call a "compatibilizer", a novel polymer that acts as a bridge between the wood fibers and the main polymer's chains.

Chemists have rolled over one of the fundamental rules of fullerene chemistry - that two pentagons cannot be neighbors - to make an egg-shaped buckyball. Virginia Tech chemist Harry Dorn and colleagues were trying to make novel medical imaging contrast agents using novel fullerenes with terbium atoms trapped inside. They sent off their products to UC Davis for structure determination but graduate student Christine Beavers working with Alan Balch and Marilyn Olmstead was very surprised to obtain an X-ray structure showing that two carbon pentagons were fused in one of the compounds. This oddity meant that rather than a symmetrical buckyball, the compound was egg-shaped. The compound's formula Tb3N@C84 reveals that three Tb atoms are trapped in this oddity and somehow lead the material to break the rule.

Physical chemistry textbooks will have to be revised yet again thanks to research led by Peter Celliers of Lawrence Livermore National Laboratory and corroborated by modeling at Sandia National Laboratories. Supercomputer simulations carried out by Sandia's Thomas Mattsson and Mike Desjarlais suggest significant changes are needed to the phase diagram for water at extreme temperatures and pressures. The theoretical work suggests that "metallic water," which can conduct electricity, could exist at temperatures as low as 4000 K and pressures of 100 GPa rather than 7000 K at 250 GPa. The new lower boundaries will require astronomers to re-evaluate their calculations of the strength of the magnetic cores of gas-giant planets such as Neptune. The planet's temperature and pressure lie within the new boundaries and might suggest that electrically conducting water contributes to the planet's magnetic field.

A new drug that is its own antidote could save patients who require anticlotting drugs from dying of internal bleeding if they inadvertently overdose on the drug. Unfractionated heparin is currently the only blood-clotting inhibitor for which a specific antidote exists. Now, Alexander Heckel, Günter Mayer, and Bernd Pötzsch in Bonn, Germany, have developed a new class of anticoagulant based on aptamers, simple strands of DNA. The new drug blocks blood clotting until it is exposed to ultraviolet light at which point an auxiliary DNA strand isomerises, distorts the drug's structure and prevents it from binding to thrombin. Its anticoagulant activity is switched off immediately.