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Crystal structure offers clues to nitric oxide regulation - C&EN Global...

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dio. I heard about the physics prize, but there was no mention of chemistry, so I assumed I could forget about that. I was consoling myself by wandering about my garden" when a German radio station phoned, "offering congratulations. . . . Then I came back to the lab and found the fax from the Swedish academy." With his prize winnings, Walker said, "I was thinking I'd buy myself a new bicycle"—a gift in keeping with the theme of rotatory catalysis. Skou was honored for his discovery, in the late 1950s, of Na+-K+ ATPase, the first enzyme found to promote directed

transport through cell membranes. This specialized ATPase maintains the proper balance of sodium and potassium ions across membranes, consuming about one-third of all the ATP produced in the body in the process. The energy stored in the ion gradients is used to drive essential cell functions, such as nerve impulse transmission. Numerous enzymes have since been demonstrated to have related similar functions—including Ca2+ ATPase, which helps control muscle contraction, and H+-K+ ATPase, which plays a key role in digestion. Stu Borman

Work on cool atoms traps Nobel Prize in Physics The 1997 Nobel Prize in Physics has been awarded to physics professors Steven Chu of Stanford University and Claude Cohen-Tannoudji of College de France and Ecole Normale Superieure, Paris, and physicist William D. Phillips at the National Institute of Standards & Technology, Gaithersburg, Md. They are being recognized for development of methods to cool and trap neutral atoms with laser light Chu, Cohen-Tannoudji, and Phillips have developed methods that allow gases to be cooled to temperatures approaching absolute zero (-273 °C) without condensing. At such temperatures, gases normally will freeze. But when bombarded with laser light, the gas atoms slow down without freezing. The slow-moving atoms then can be trapped in magnetic fields and studied in detail

China captures more petrochemical investments The lure of double-digit growth continues to draw U.S. chemical companies to China. Last week, petrochemical giants Exxon and Phillips Petroleum each announced plans for new chemical complexes expected to begin supplying the huge Chinese market by early next century. Exxon China, an affiliate of Exxon, will be joined by Saudi Arabia's Aramco in a feasibility study with Fujian Petrochemical Co. (FPC) to build a refinery and petrochemical complex in Fujian Province of central China. The project involves the expansion of an existing FPC refinery and the addition of a 1.3 billionlb-per-year ethylene cracker, a 1 billionlb-per-year polyethylene facility, and a 12 OCTOBER 20, 1997 C&EN

By allowing the study of atomic properties with greater accuracy than has been possible before, the methods "have contributed greatly to increasing our knowledge of the interplay between radiation and matter" and "have opened the way to a deeper understanding of the quantumphysical behavior of gases at low temperature," says the Royal Swedish Academy of Sciences, which decided the award "Applications [are] just around the corner," adds the academy. Already, the techniques have led to thefirstobservation of Bose-Einstein condensate, a new state of matter in which many atoms assume a common quantum state. Other possible applications include design of ultraprecise atomic clocks and development of atomic lasers for production of very small electronic components. Maureen Rouhi 660 million-lb-per-year polypropylene facility for completion in 2003. When the project was first announced in August, Exxon was to be an equal partner with FPC (C&EN, Aug. 11, page 15), but the Exxon portion will now be shared with Aramco, which will provide the crude oil feedstock for the facility. At a Beijing signing ceremony on Oct. 10, Phillips and local manufacturers announced their plans for three petrochemical ventures, to be built following feasibility studies. The first is a $2.4 billion chemical complex, split equally with Lanzhou Chemical Industry Corp. (LCIC), that would include a 1.3 billion-lb-per-year ethylene cracker and annual polymer capacity of 1.2 billion lb of polyethylene and 660 million lb of polypropylene. The proposed complex would be located at an existing LCIC facility in central China and would start up in 2004 or 2005. Phillips also has plans for a new

100 million-lb-per-year styrene-butadiene copolymer facility and an expansion of a joint polyethylene facility with Shanghai Petrochemical in Jinshanwei on China's central coast, near Shanghai. The polyethylene expansion will triple capacity to 750 million lb per year at a facility currently under construction. Completion of the copolymer plant and the expansion are set for 2002. W. Wayne Allen, chairman and chief executive officer at Phillips, notes that these projects "demonstrate our commitment to China and its efforts to build a world-class petrochemical industry." The influx of foreign money is important to the development of the petrochemical industry in China, according to Dave Durand of Phillip Townsend Associates, Houston. Many of the existing production units are small and isolated; large, well-integrated complexes are needed to meet the growing local demand. Durand predicts annual growth rates of 11 to 12% for polyethylene and 13% for polypropylene in China for the next five years. China continues to rely heavily on imports of polyolefin products. In 1996, 58% of polyethylene demand and 45% of polypropylene demand were met with imported products. With China's polyethylene market second in size only to the U.S., Exxon and Phillips are eager to take advantage of the large opportunity there with shared local production. Paige Morse

Crystal structure offers clues to nitric oxide regulation Researchers are getting their first look at the catalytic portion of the enzyme that makes the signaling molecule nitric oxide (NO). An X-ray crystal structure of that key part of one form of nitric oxide synthase likely will yield clues to how the body makes and regulates the production of the reactive free radical. Short-lived NO serves as a messenger in processes as diverse as neural signaling, blood pressure control, and immune regulation. It's also used defensively by the immune system to fight infection. Too much or too little NO has been implicated in many serious conditions including septic shock, hypertension, impotence, and susceptibility to infection. "Here's a molecule that can walk

possible to design molecules to inhibit specific forms of the enzyme, Ignarro says, thereby affecting some of NO's many biological functions without disrupting them all. "We've shone a light on one part of this very interesting enzyme system," Tainer says, "and we now know quite a bit about the heme environment" where NO is cleaved from L-arginine. "It really looks to us like the arginine itself is facilitating the reaction," he says, noting that this is a controversial explanation of how the enzyme might operate. The structure "suggests the kind of experiments to do to verify this or disprove it." Rebecca Rawls

Hemoglobin, center left, rests like the ball in a catcher's mitt in the catalytic site of nitric oxide synthase.

through walls, that can 'toast' its enemies," says crystallographer John A. Tainer of Scripps Research Institute, La Jolla, Calif. "It's an oxidant for pathogens and it's a chemical signal, and those two things are regulated by one enzyme that, strangely enough, makes NO by starting with arginine. It really catches your imagination." Along with biochemist Dennis J. Stuehr at the Cleveland Clinic in Ohio, Tainer led the team that solved the structure [Science, 278, 425 (1997)]. Key to the solution, Tainer says, was the work of former graduate student Brian R. Crane (now at California Institute of Technology) and Scripps scientific associate Andrew S. Arvai. "This is an outstanding achievement, the culmination of an immense amount of work," says Jack L. Lancaster, professor of medicine at Louisiana State University Medical Center in New Orleans and a researcher on NO. "One of the major black boxes in this field has been how this complex enzyme makes NO from L-arginine, dioxygen, and the cofactor nicotineadenine dinucleotide phosphate. Although it was known that the reaction superficially resembles those carried out by the cytochrome P450 class of enzymes, it now becomes clear that NO synthase is its own enzyme," he explains. The structure "is important and informative to those of us working in the field of NO research," says Louis J. Ignarro, professor of molecular pharmacology at the University of California, Los Angeles, School of Medicine. Among other things, the structure suggests that it should be

National Science Board meets in Houston, tackles policy issues The National Science Board (NSB), the governing body of the National Science Foundation, held its first off-site meeting in Houston just over a week ago. The board, which usually meets at NSF headquarters in Arlington, Va., intends to hold at least one meeting a year at another location. The meetings, which will focus on important national science policy topics, are a way of getting input from communities outside the Washington area. In Houston, NSB looked at two topics—a working paper on priorities in government funding of scientific research, and graduate and postgraduate education. The brief working paper finally has been accepted by the group and, after minor editing, probably will be sent to White House science adviser John H. Gibbons for comment. By its next meeting in mid-November, NSB expects to be able to decide about making it public. However, NSB, which has been working on the document for about one and a half years, thought it was nearly done once before (C&EN, Sept. 1, page 12). At Gibbons' request, NSB is looking into the federal role in science and engineering graduate and postgraduate education. Its effort is part of a broader review of the government/university partnership being conducted by the National Science & Technology Council (NSTC). At the Houston meeting, directors from government agencies and nearly a dozen representatives from academe

spoke to the national interest and federal involvement in graduate education, and addressed related needs, issues, and tensions between universities and the government. Among the questions broached were those of funding, infrastructure, and other costs; the status of graduates as students versus employees; diversity and foreign enrollment; and appropriate training and employment. Malcolm Gillis, president of Rice University in Houston, noted that "higher education is receiving perhaps more mixed messages from government today than at any time in the decades-long university/ government partnership." But, he added, "research universities have agonized long and loudly over problems stemming from the external environment, while devoting little more than lip service to problems primarily of our own making. It is time to redress that imbalance." Despite poor local turnout, the presentations prompted much discussion among NSB members and a decision to produce an extensive review of the subject and more prescriptive recommendations. The board is moving quickly to produce a working paper on education in time to meet NSTC's new January 1998 deadline for publication of its report. The report had been due in August (C&EN, March 24, page 34). Ann Thayer

Congress revives chemical accident board Buried in the Environmental Protection Agency's fiscal 1998 appropriation recently approved by Congress is $4 million for an independent chemical accident investigative board. The board was created in 1990, when the Clean Air Act was last amended, but never put into operation. Its fate remains uncertain, despite support from some 80 community, environmental, and labor organizations, and from the governors of West Virginia and New Jersey, the American Institute of Chemical Engineers, and a few chemical companies. President Bill Clinton opposes the board and may use his new line-item veto power to deep-six it once again. Similar in design to the National Transportation Safety Board, the Chemical Safety & Hazard Investigation Board was established to provide an independent assessment of chemical accidents. President OCTOBER 20, 1997 C&EN 13