n e w s of t h e w e e k - P ^ · &&&&,

derstanding of how proteins interact with RNA.

"Just seeing the architecture of how this whole thing is put together is neat!" Steitz says. "I think it's going to be an in­credible database for understanding how RNA folds. Everybody—including ourselves—will look at this RNA struc­ture and ask: What are the principles of folding in RNA? And can we use these principles to predict the structure of oth­er RNA?"

At least one atomic resolution struc­ture of the other subunit of the ribosome is expected shortly. Venki Ramakrish-nan, an investigator at the Medical Re­search Council Laboratory, Cambridge, England, says he has two papers on this structure in press, including views of the subunit complexed with three differ­ent antibiotics. Both the Yale and Cam­bridge groups published lower resolu­tion structures of their respective sub-units last year (C&EN, Aug. 30, 1999, page 14).

Like Ramakrishnan, the Yale group is also investigating the interactions of their subunit with various antibiotics. "We are going to be able to get in­volved in structure-based drug design with our structure at quite a respect­able level, I believe," Steitz says. The ribosome is one of the most important targets of existing antibiotics, he notes, which makes it of prime interest for future drug design. Although their plans are still in flux, Steitz anticipates that the Yale group will start a small biotechnology company in New Haven that will work with various pharmaceu­tical houses on structure-based drug design.

Rebecca Rawls

Profits Up For German Chemical Producers The first half of this year smiled on Ger­man chemical companies, according to results released last week by major pro­ducers BASF, Bayer, Celanese, and SKW. But one or two niggling signs in second-quarter results indicate that raw material and energy cost increases are starting to eat into profitability.

At BASF, which is the world's largest chemical company, first-half sales were $15.7 billion, up 24.5% from the compa­rable period in 1999. Net income was $820 million, an improvement of 113%. Second-quarter sales of $8.07 billion set

a record, BASF said. Net profits for the second quarter were $403 million, an in­crease of 323%, reflecting large extraor­dinary charges taken in the second quarter of last year.

Second-quarter operating profits be­fore special charges were $794 million, up 18% over the same period in 1999. However, the company said, "a number of divi­sions were ex­posed to notice­able pressure on margins, as a result of increased raw material prices. To date, this effect has been only partially offset by increases in selling prices."

First-half sales from continuing oper­ations at Bayer totaled $13.9 billion, up 22% from the same period of last year. However, first-half net profits declined 40% to $929 million. Last year's first-half figures included nearly $900 million in revenues from the spin-off of the com­pany's Agfa photographic division.

In the first six months of the year, Bayer rang up double-digit sales growth in all of its business segments and re­gions, while operating profits improved for all divisions except its chemicals unit. There, though sales rose 17% over first-half 1999 to $1.89 billion, operating profits declined 4% to $223 million be­cause of "sharp increases in raw materi­al prices." Conversely, operating profits for Bayer's health care operations rose 68% to $672 million on sales of $4.26 bil­lion, a 21% increase.

At Celanese, second-quarter sales were up 19% to $1.17 billion, and operat­ing profits were up 69% to $99 million. The company posted net profits of $23 million in the quarter, compared with a loss of $200 million in second-quarter 1999, engendered by Celanese's split from Hoechst last year.

The operating profit margin for the second quarter, excluding special charges, was 8.5%, up 6% from the sec­ond quarter of last year. However, the comparable figure in the first quarter of 2000 was 13.9%. Claudio Sonder, Cela­nese chief executive officer and chair­man, said, "We did not perform as well as in the first quarter, largely because of rapidly rising raw material and energy costs."

SKW, in one of its last reports prior

to its merger with Degussa-Hiils later this year, showed "a very successful first half," the company said. "The strong growth seen in the record figures both last year and in the first quarter of 2000 con­

tinued at the same pace in the second quarter," with

sales and operating profits increasing "substantially."

Sales for the half were $1.86 bil­lion, up 27% over first-half 1999;

operating prof­its were up 21%

to $277 million. All four of the compa­

ny's divisions—construction chemicals, nature products, perfor­

mance chemicals, and oligomers/sili­cones—contributed to the growth, SKW said.

Patricia Short

Nuclear Weapons: Cleanup Without End Forever is a long time, but that's how long watchful monitoring and isolation from humans will be required at more than 100 former U.S. nuclear weapon sites, a National Research Council re­port says.

Department of Energy cleanup plans for these sites, the report says, do not fully recognize the role of long-term stewardship, nor the likelihood that en­gineered barriers and other techniques used to isolate radioactive and hazard­ous waste will fail long before time has rendered the wastes safe.

The report questions DOE assump­tions that site stewardship will be a low-cost operation, compared to the $250 bil­lion cleanup price tag. Stewardship could stretch to thousands of years, the report says, and costs could skyrocket if DOE scientists underestimate the price of solutions to difficult cleanup prob­lems, such as the flow of contaminated groundwater.

Because of the extreme timescale, the report says, stewardship must in­clude careful watching of land use near sites, especially in rapidly growing areas such as Denver, near the Rocky Flats site, and Las Vegas, near the Nevada Test Site.

Monitoring and oversight must en­tail more than signs, fences, or deeds

10 AUGUST 14,2000 C&EN

of sale. The report singles out DOE's Oak Ridge facility in Tennessee, where land sold to a golf course developer carried the stipulation that contaminat­ed groundwater not be tapped. Despite the restriction, however, the owner soon began drilling for water.

The report also notes that technical solutions may not work or may take hundreds of years. It cites a groundwa­ter containment operation at the Han-ford Reservation in Washington state in­tended to retard migration of strontium-90 to the Columbia River. Strontium-90 has the benefit of a short, 29-year half-life, compared with other radioactive wastes, but the pump and reinject facili­ty at Hanford will have to run for 300

| Columbia River flows ο through DOE's Hanford I Nuclear Reservation.

years for radiation to decay to safe levels.

The report urges DOE to fully integrate stewardship into clean­up plans.

DOE commissioned and agrees with much of the report, says Ger­ald G. Boyd, deputy as­sistant secretary for sci­ence and technology in

DOE's Office of Environmental Man­agement. DOE must actively monitor for "100, 200, or 1,000 years—whatever it takes," he says, "but we think we can lay out a cost-effective program."

Using the Hanford example, he says, 'We may find a better way to treat stron­tium in groundwater in the future, cut­ting costs and time." He argues, howev­er, that DOE can't wait for long. "We need to get the waste stable and in a safe condition quickly," he says.

DOE created a Long-Term Steward­ship Office last November with a $5 mil­lion yearly budget, Boyd points out. It will issue a stewardship assessment in October.

Jeff'Johnson

Nature Spurs Design Of Iron-Oxo Complex Taking their inspiration from biological reactions, chemists have succeeded in synthesizing a unique artificial iron-oxy­gen complex that's not only stable enough to be characterized, but also provides a new springboard for study and design of catalytic complexes.

Nature routinely performs oxida­tion with the help of iron-containing catalysts that activate molecular oxy­gen. It's believed that heme enzymes such as cytochrome P450 and non-heme enzymes such as methane mo-nooxygenase split 0 2 apart, grabbing one of the oxygens and forming an in­termediate oxo complex. These com­plexes then go on to perform chemical reactions, like the oxidation of meth­ane to methanol.

Top view ofiron-oxo complex reveals cavity formed by the ligand surrounding oxygen (red). Iron is shown as orange;

carbon, gray; hydrogen, white; and nitrogen (barely visible), blue.

But these intermediates have been notoriously difficult to pin down. The structures of synthetic heme-based complexes have been moderately char­acterized, but the structures of non-heme-based complexes had until now only been inferred from mechanistic studies. And attempts to synthesize arti­

ficial nonheme iron-oxo complexes have been hindered by the fact that the molecules tend to form unreactive, oxo-bridged dimers.

The new synthetic monomelic iron-oxo complex, which doesn't suffer from such limitations, was created by associ­ate chemistry professor Andrew S. Borovik and graduate student Cora E. MacBeth at the University of Kansas in Lawrence, associate chemistry profes­sor Michael P. Hendrich at Carnegie Mellon University in Pittsburgh, and their colleagues.

Knowledge about biological process­es gave them insight into how to design the synthetic system, MacBeth says. 'The best way to couch it is to say that it's bioinspired," Borovik says.

Their success hinges on the design of a new ligand system—which col­leagues have described as elegant— that forms a cavity, surrounding the ox­ygen atom of an Fe-0 unit with stabiliz­ing hydrogen bonds [Science, 289 , 938 (2000) ]. The authors say this type of hy­drogen bonding near unsaturated metal centers is probably what's going on in the complex's biological analogs. Hy­drogen-bond donors have been pro­posed in heme enzymes such as cyto­chrome P450, and although the picture is muddier in the case of nonheme en­zymes, Borovik says, "there's a reason­able amount of evidence that hydrogen bonds play a crucial role in regulating dioxygen activation."

One unique aspect of the system is that two of the iron-oxo complexes are formed from 0 2 activated by the complex's precursor, as opposed to the one complex formed in biological systems.

'Without a doubt, these complexes are benchmark structures for our un­derstanding of nonheme metallopro-

teins and their 0 2 activation," notes Karl Wieghardt, chemistry profes­sor and managing director at the Max Planck Institute of Radiation Chemistry, Mulheim an der Ruhr, Germany.

Calling the research "a big ad­vance in bioinorganic chemistry," H. Holden Thorp, associate chemistry professor at the University of North Carolina, Chapel Hill, says the ligand design has great tailoring potential. And the group members now want to do just that: By manipulating the li-gands, they say they may be able to tune the molecule's reactivity.

Elizabeth Wilson

AUGUST 14, 2000 C&EN 11