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At press urne, bugene Coram, bureau of Export Administration spokesman, said the number "is considerably beyond 534, but I can't offer a precise figure." This gag order, however, leads some to believe the numbers are disappointing. "Commerce would have said something if the news were good," says Leslie-Anne Levy, research associate at the Stimson Center, a Washington, D.C., national se curity research organization. An estimated 2,000 sites that pro duce, consume, or import/export trea ty-listed chemicals are required to re port certain data on these chemicals for 1996 through 1999. A majority of these sites will eventually be visited by OPCW inspectors to confirm reported data. Sites reporting Schedule 1 or Sched ule 2 chemicals are likely to be visited by OPCW inspectors beginning in May. Schedule 1 chemicals are actual chemical weapons, and Schedule 2 chemicals are immediate precursors to these weapons but have legitimate commercial uses. In spections of facilities reporting Schedule 3 chemicals would follow. But the majori ty of sites—those producing so-called un scheduled discrete organic chemicals— are not likely to be inspected in the near future, Goldman said. 'We're in a holding pattern now," says Marybeth Kelliher, Chemical Manufac turers Association spokeswoman on CWC issues. 'The exact number of decla rations is not yet known and that number will tip off debate within The Hague and here at home about the number of U.S. industry inspections to expect this year." OPCW has budgeted for about 40 U.S. industry inspections this year. However, the U.S. has informed OPCW that it can host only 18 to 26 inspections in 2000. Most industrial sites in other major chemical producing/processing countries have already been inspected at least once. Lois Ember
A designed (J-peptide could be the har binger of a new class of compounds for treating infections that are resistant to current antibiotics. Called P-17, the (J-peptide is active against four species of bacteria, includ ing vancomycin-resistant Enterococcus faecium and methicillin-resistant Staph ylococcus aureus. (3-17 was developed by APRIL 10, 2000 C&EN
branes. As potential therapeutic agents, they are notable for their broad spec trum of activity and their low potential to induce resistance in bacteria, explains Michael Zasloff, discoverer of the ma gainins and vice chairman of Magainin Pharmaceuticals, Plymouth Meeting, Pa. "What impresses me is the simplici ty" of p-17, Zasloff says. "It is composed of only two monomelic units, yet it re tains the selectivity that is characteristic of natural antimicrobial peptides." The origin of that selectivity is still unre solved, he notes, adding that P-17 "might help us understand that more clearly than we do at present." P-Peptides are foldamers—that is, oligomers that adopt a specific confor mation in solution. Coming into the chemical scene in the mid-1990s as in teresting synthetic targets, they—as well as other foldamers not based on P-amino acids (see page 48)—are now being scrutinized for possible function. The work is "fantastic," comments Annelise E. Barron, an assistant — professor of chemical engineering at Northwestern University, EvansH9N ton, 111. As a researcher interested in the design of bioactive peptide mimics, she says the Wisconsin team's results "strengthen my be lief in the bright future of nonnatural oligomers with ordered sec ondary structures for therapeutic applications." Researchers find p-peptides at tractive as potential therapeutic agents because they are resistant to enzymes that break down natural peptides and proteins. For exam ple, the group of William F. DeGrado, a professor of biochemistry at the University of Pennsylvania School of Medicine, recently de scribed p-peptides with surface properties similar to those of p-17. The peptides made by DeGrado —"3 comprise acyclic p-amino acid resi dues and adopt a helical conforma tion that is different from that of p-17. They are highly active against Escherichia coli, but also against red blood cells \J. Am. Chem. Soc, 121,12200(1999)]. The structural differences be tween the two types of P-peptides, β-17 Gellman believes, will ultimately help explain why one type attacks Oxygens are shown in red, nitrogens in bacteria selectively and the other dark blue, hydrogens in light blue, and does not. carbons in gray. Maureen Rouhi
Samuel H. Gellman, a professor of chemistry; Bernard Weisblum, a profes sor of pharmacology; graduate student Emilie A. Porter; and postdoctoral asso ciates Xifang Wang and Hee-Seung Lee at the University of Wisconsin, Madison [Nature, 404, 565 (2000)]. It is composed of the p-amino acids (/?,i?)-£raws-2-aminopentanecarboxylic acid and (3/?,4S)-fraws-4-aminopyrrolidine-3-carboxylic acid. P-17 folds into a helix similar to that formed by the natu ral peptide antibiotics called the magainins—that is, it has hydrophobic side chains on one side of the helix and cationic side chains on the other. The (J-peptide's activity against bac teria is similar to that of a magainin de rivative, the Wisconsin team finds. In addition, it is only very weakly hemolyt ic, even less so than the magainin deriv ative. (Hemolysis refers to the breaking of red blood cells, which is not desirable for therapeutic applications). Magainins are believed to destroy bacteria by disrupting bacterial mem-
Slaying Bacteria With (^-Peptides
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