NEWS OF THE WEEK
EPA SETS SCHEDULE FOR CO2 REGULATION GREENHOUSE GASES: Agency takes next step to cut industry emissions Y MIDYEAR 2012, refineries and fossil-fuelfired electric utilities will be required to begin lowering their greenhouse gas emissions under a recent court settlement reached by the Environmental Protection Agency and several states and environmental groups. Refineries and power plants are responsible for 40% of U.S. greenhouse gas emissions, EPA said when making the announcement on Dec. 23. Under the settlement, EPA will use Clean Air Act regulations to propose emissions standards for power plants in July 2011 and for refineries in December 2011 and to issue final regulations in May and November 2012, respectively. EPA has not determined what the standards will be, however, and the agency said the lengthy schedule allows it to host several “listening sessions” with businesses, states, and other stakeholders early in 2011 as it draws up actual regulations.
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RARE SUGAR LINKAGE REVEALED CHEMICAL BIOLOGY: Stable modified peptide leads team to a promising enzyme for synthesis RARE MODIFICATION TO peptides—sugar attachment through the sulfur of cysteine—may be more common than chemists have suspected, according to a study in Nature Chemical Biology (DOI: 10.1038/nchembio.509). The work also uncovers an enzyme that could build longlasting sugar-peptide conjugates FLEXIBLE The enzyme that that could be used to generate antinormally installs glucose (red) bodies and study antibiotics. on sublancin can transfer other Graduate student Trent J. Oman, sugars to make sublancin analogs professor Wilfred A. van der Donk, instead. and colleagues at the University of OH Illinois, Urbana-Champaign, stumHO OH bled on the special sulfur linkage O while studying sublancin, a naturally Sublancin S OH occurring bacterial peptide whose biosynthesis was a mystery. Sublancin was thought to belong to a class of peptide antibiotics called lantibiotics, but the microbe that makes
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“We are following through on our commitment to proceed in a measured and careful way to reduce greenhouse gas pollution that threatens the health and welfare of Americans, and contributes to climate change,” EPA Administrator Lisa P. Jackson said in a statement. The standards, she added, will provide clarity and help U.S. companies attract private investments needed to fund the clean energy upgrades. A host of fossil-fuel trade associations, manufacturers, and other industry representatives blasted the agency’s plans, saying it would be expensive and would drive jobs and manufacturing to other nations. The new chairman of the House of Representatives’ Energy & Commerce Committee, Fred Upton (R-Mich.), promised aggressive committee oversight of EPA and called the plan “a backdoor attempt to implement [the Administration’s] failed job-killing cap-and-trade scheme.” Efforts to stop EPA from regulating greenhouse gases through the Clean Air Act have been led by chemical companies, manufacturers, and their allies in Congress and are likely to continue this year. The Administration’s approach, however, has been defended by several states and environmental groups, such as the Natural Resources Defense Council, which is one of the litigants. NRDC called the settlement terms “precisely what is needed to protect our health and welfare and provide businesses certainty.”—JEFF JOHNSON
it doesn’t have any lantibiotic-making machinery, van der Donk explains. His team’s mass spectrometry data show that sublancin lacks the dehydroalanine amino acid residue that is typical of lantibiotics. Instead, it has glucose attached to one of its five cysteine thiols, making it an S-linked glycopeptide. Few S-linked glycopeptides have been discovered, but protein database searches suggest sublancin isn’t a fluke—it appears to be part of a family of yet to be studied peptides. “You’d think that by 2010, many of these peptides would have been found, but maybe we weren’t looking for the right things,” van der Donk says. In addition, the team observed that the enzyme attaching glucose to sublancin accepts a variety of building blocks, including different sugars. This could make the enzyme valuable for chemical synthesis, van der Donk says. S-linked glycopeptides are more stable than other types of glycopeptides, so chemists have sought them as potential drugs and as tools for biological research, in particular to generate antibodies that track glycopeptides, he explains. The team would still like to find out how the enzyme selectively installs a sugar on just one of sublancin’s five cysteines and hopes to use analogs to learn how sublancin works as an antibiotic. The sugar-installing enzyme has exciting potential as a synthetic tool, glycochemist Linda C. Hsieh-Wilson of Caltech agrees. “Nature continues to surprise us with its chemical ingenuity.”—CARMEN DRAHL
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