ELEVATING OXYGEN Technique yields unprecedented resolution in 17O NMR spectra of proteins in solution SPECTROSCOPY:
XYGEN IS the ugly duckling of biomolecular
O
nuclear magnetic resonance. Although it is a key atom in proteins and nucleic acids, its siblings carbon, hydrogen, nitrogen, and phosphorus are analyzed far more often because 17O-based NMR spectra are poorly resolved. Now, in an effort to promote oxygen to its rightful place, researchers have developed a method that makes it more practical to obtain solution NMR spectra of 17O in biomolecules with much better resolution than was possible before. Postdoc Jianfeng Zhu and NMR spectroscopist Gang Wu at Queen’s University, in Kingston, Ontario, developed the method (J. Am. Chem. Soc., DOI: 10.1021/ ja1079207). Wu and coworkers earlier reported the use of ultrahigh magnetic fields to analyze large proteinligand complexes for the first time by solid-state 17O NMR spectroscopy (Angew. Chem. Int. Ed., DOI: 10.1002/ anie.201002041). In the new work, they developed a technique called quadrupole central transition NMR that enabled them to extend high-resolution 17O NMR to the analysis of biomolecules in aqueous solution. Both studies achieved unprecedented levels of resolution for 17O NMR, and the solution method increases the size limit of 17O-containing biomolecules accessible to NMR analysis by nearly three orders of magnitude over previous efforts. The solution technique is the more important, Wu says, “because it permits one to study biological molecules such as proteins in the native state” instead of in a rigid crystalline form. The work “clearly shows that highly resolved 17O spectra of even quite large proteins can be obtained at very high magnetic fields,” says Eric Oldfield of the Uni-
versity of Illinois, Urbana-Champaign, who did pioneering work on biomolecular 17O NMR in the 1980s. “The challenge now is to label proteins and more-complex ligands” because it is difficult and expensive to make 17 O-labeled proteins and complex ligands, he notes. 17 O NMR is difficult because 17O is a quadrupolar nucleus, a type that generates broad, difficult-to-interpret 17O SPECTRUM Quadrupole central NMR spectral lines. Zhu and transition NMR delivers separate Wu addressed this challenge 17O NMR peaks for the four oxygens by applying unusually high (O1 to O4) in this protein oxalate magnetic fields and focusing ligand—a level of resolution never on just a single type of NMR before obtained for oxygen in proteins. energy change, called the Dashed lines are hydrogen bonds, central transition. These stratArg = arginine, His = histidine, Thr = egies—and the tendency of threonine, Tyr = tyrosine, Gly = glycine, large biomolecules in solution and Ala = alanine. to move slowly, which curbs broadening—enabled the reWater searchers to reduce 17O NMR His 249 Arg 124 line widths and thus improve resolution considerably. O4 Quadrupole central tranThr 120 O1 sition NMR could be used Al to study bonding effects O2 on oxygen chemical shifts, oxygen-containing reaction O3 intermediate formation, and oxygen-containing ligand Tyr 95 binding in biomolecules— Gly 127 Ala 126 such as the binding of oxalate to ovotransferrin, a subject of 01 02 03 04 the new study. Wu and coworkers believe the new technique could be applicable to protein complexes of up to 500 kDa—and perhaps also make the 17O ugly 300 270 240 210 180 150 duckling a lot less lonely.—STU ppm BORMAN
PHARMACEUTICALS Eyeing new market, Novartis will invest $500 million in Russia Novartis has signed an agreement to build a pharmaceutical manufacturing facility in St. Petersburg, Russia. The plant is part of a $500 million Novartis investment in infrastructure, health care initiatives, and R&D in Russia over the next five years. The Swiss company says construction will begin this year on a facility to which it will transfer technology for both generic and innovative pharmaceuticals. “This collaboration shows our commitment to contributing to the ambitious health care goals of the Russian government,” Novartis CEO Joseph Jimenez says.
In addition to building the plant, Novartis says it will invest in research collaborations that may include outlicensing Novartis compounds to qualifying Russian companies and in-licensing compounds from Russian scientists and universities. Novartis has also committed to doubling its investment in drug development and clinical trials in Russia. The announcement follows a pledge late last year by Russian Prime Minister Vladimir Putin of some $4 billion in federal funding for pharmaceutical industry development over the next 10 years. The
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government has set a goal for local industry to produce 90% of Russia’s “essential medicines”—about half of the country’s total pharmaceutical sales—by 2020. According to Michael Kleinrock, director of market insights at IMS Health, Russia is a “high potential” emerging market for multinational drug companies as it follows the lead of China and India in developing its domestic drug industry. “They understand there is a linkage between the science and the benefit for health care,” Kleinrock says.—RICK MULLIN
J. AM . CHEM. SOC.
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