研究领域

Analytical Chemistry/Bioanalytical Chemistry/Bioinorganic Chemistry/Biophysical Chemistry/Chemical Biology/Energy Science/Inorganic Chemistry/Materials Chemistry/Nano Chemistry/Optics and Imaging/Organometallic Chemistry/Physical Chemistry/RNA BioChemistry/Sustainable Chemistry

Metalloenzymes (proteins with metals at their active sites) catalyze reactions with a speed and selectivity that is unrivaled by conventional catalysts. We want to understand how metalloenzymes work. Our approach is to correlate metal-site structure with enzymatic function. Currently, we are studying manganese redox enzymes and zinc containing proteins. Virtually all of the O2 in the atmosphere is produced by the photosynthetic oxygen evolving complex, a Mn/Ca/Cl cluster that catalyzes the oxidation of H2O to O2. Other manganese enzymes include Mn catalase and superoxide dismutase. By comparing these Mn structures, we have been able to develop a better understanding of the bioinorganic chemistry of Mn. Our ultimate goal is to understand, in detail, how plants make oxygen. Zn has recently been shown to play a critical role in catalyzing the transfer of alkyl groups to thiol acceptors, forming thioethers. The enzymes, which are involved in a number of critical reactions, ranging from homocysteine homeostasis to protein farnesylation to alkene metabolism, generally contain thiolate-rich Zn sites. We want to understand the mechanism of Zn-promoted alkyl transfer. How does Zn(II) promote nucleophilic attack of a thiol on an alkyl donor? In addition to its enzymatic roles, Zn also plays a critical role in controlling development. High Zn levels (ca. 1 mM) have been found in fish and frog eggs, and recently we have shown that the chemical environment of this Zn changes following fertilization. We are now using spectroscopy, microscopy, and biochemistry to characterize this Zn, and developing analytic methods for tracking the distribution of the Zn through cells during development. Why is Zn present in high concentrations, what roles does it play, and how it is able to control development? We make extensive use of synchrotron radiation, using the unique resources available at synchrotron laboratories in the US (Brookhaven, Argonne, Stanford) and abroad (Japan, France). A key technique is X-ray absorption spectroscopy. This is one of the only ways to obtain detailed structural information for non-crystalline systems. In addition to X-ray methods, we make use of a wide range of other spectroscopies, including EPR, IR, and paramagnetically-shifted NMR.

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Weng, T. C.; Waldo, G. S.; Penner-Hahn, J. E. "A method for normalization of X-ray absorption spectra" Journal of Synchrotron Radiation 2005, 12, 506-510. Link. Penner-Hahn, J. E.; Yocum, C. F. "The Photosynthesis "Oxygen Clock" Gets a New Number" Science 2005, 310, 982-983. Link. Penner-Hahn, J. E. "Characterization of "spectroscopically quiet" metals in biology" Coord. Chem. Rev. 2005, 249, 161-177. Magyar, J. S.; Weng, T. C.; Stern, C. M.; Dye, D. F.; Rous, B. W.; Payne, J. C.; Bridgewater, B. M.; Mijovilovich, A.; Parkin, G.; Zaleski, J. M.; Penner-Hahn, J. E.; Godwin, H. A. "Reexamination of lead(II) coordination preferences in sulfur-rich sites: Implications for a critical mechanism of lead poisoning" J. Am. Chem. Soc. 2005, 127, 9495-9505. Link. Lansky, D. E.; Mandimutsira, B.; Ramdhanie, B.; Clausen, M.; Penner-Hahn, J.; Zvyagin, S. A.; Telser, J.; Krzystek, J.; Zhan, R. Q.; Ou, Z. P.; Kadish, K. M.; Zakharov, L.; Rheingold, A. L.; Goldberg, D. P. "Synthesis, characterization, and physicochernical properties of manganese(III) and manganese(V)-oxo corrolazines" Inorg. Chem. 2005, 44, 4485-4498. Link. Zharov, I.; Weng, T. C.; Orendt, A. M.; Barich, D. H.; Penner-Hahn, J.; Grant, D. M.; Havlas, Z.; Michi, J. "Metal cation-methyl interactions in CB11Me12- salts of Me3Ge+, Me3Sn+, and Me3Pb+" J. Am. Chem. Soc. 2004, 126, 12033-12046. Link. Wu, A. J.; Penner-Hahn, J. E.; Pecoraro, V. L. "Structural, spectroscopic, and reactivity models for the manganese catalases" Chem. Rev. 2004, 104, 903-938. Link. Weng, T. C.; Hsieh, W. Y.; Uffelman, E. S.; Gordon-Wylie, S. W.; Collins, T. J.; Pecoraro, V. L.; Penner-Hahn, J. E. "XANES evidence against a manganyl species in the S-3 state of the oxygen-evolving complex" J. Am. Chem. Soc. 2004, 126, 8070-8071. Link. Masip, L.; Pan, J. L.; Haldar, S.; Penner-Hahn, J. E.; DeLisa, M. P.; Georgiou, G.; Bardwell, J. C. A.; Collet, J. F. "An engineered pathway for the formation of protein disulfide bonds" Science 2004, 303, 1185-1189. Link. Kuntzleman, T.; McCarrick, M.; Penner-Hahn, J.; Yocum, C. "Probing reactive sites within the Photosystem II manganese cluster: Evidence for separate populations of manganese that differ in redox potential" Phys. Chem. Chem. Phys. 2004, 6, 4897-4904. Link. Hsieh, W. Y.; Campbell, K. A.; Gregor, W.; Britt, R. D.; Yoder, D. W.; Penner-Hahn, J. E.; Pecoraro, V. L. "The first spectroscopic model for the S-1 state multiline signal of the OEC" Biochim Biophys Acta 2004, 1655, 149-157. Clot, E.; Eisenstein, O.; Weng, T. C.; Penner-Hahn, J.; Caulton, K. G. "Is the allylpalladium structure altered between solid and solutions?" J. Am. Chem. Soc. 2004, 126, 9079-9084. Link. Tobin, D. A.; Pickett, J. S.; Hartman, H. L.; Fierke, C. A.; Penner-Hahn, J. E. "Structural characterization of the zinc site in protein farnesyltransferase" J. Am. Chem. Soc. 2003, 125, 9962-9969. Link. Penner-Hahn, J. E. "Snapshots of transition states?" Nature Struct. Biol. 2003, 10, 75-77. Peariso, K.; Huffman, D. L.; Penner-Hahn, J. E.; O'Halloran, T. V. "The PcoC copper resistance protein coordinates Cu(I) via novel S-methionine interactions" J. Am. Chem. Soc. 2003, 125, 342-343. Link. McClure, C. P.; Rusche, K. M.; Peariso, K.; Jackman, J. E.; Fierke, C. A.; Penner-Hahn, J. E. "EXAFS studies of the zinc sites of UDP-(3-O-acyl)-N-acetylglucosamine deacetylase (LpxC)" J. Inorg. Biochem. 2003, 94, 78-85. Chen, K.; Yuldasheva, S.; Penner-Hahn, J. E.; O'Halloran, T. V. "An atypical linear Cu(I)-S-2 center constitutes the high-affinity metal-sensing site in the CueR metalloregulatory protein" J. Am. Chem. Soc. 2003, 125, 12088-12089. Link. Alexiou, M.; Dendrinou-Samara, C.; Karagianni, A.; Biswas, S.; Zaleski, C. M.; Kampf, J.; Yoder, D.; Penner-Hahn, J. E.; Pecoraro, V. L.; Kessissoglou, D. P. "Models for the lower S states of photosystem II: A trinuclear mixed-valent Mn-II/Mn-IV/Mn-II complex" Inorg. Chem. 2003, 42, 2185-2187. Link. Penner-Hahn, J. E. "Zn catalyzed alkyl-transfer reactions: A new class of biological Zn sites" Indian Journal of Chemistry Section a-Inorganic Bio-Inorganic Physical Theoretical & Analytical Chemistry 2002, 41, 13-21. Matzapetakis, M.; Farrer, B. T.; Weng, T. C.; Hemmingsen, L.; Penner-Hahn, J. E.; Pecoraro, V. L. "Comparison of the binding of cadmium(II), mercury(II), and arsenic(III) to the de novo designed peptides TRI L12C and TRI L16C" J. Am. Chem. Soc. 2002, 124, 8042-8054. Link.