We investigate the mechanisms of oxygenases, the enzymes nature uses to catalyze the incorporation of oxygen into biological molecules. Oxygen incorporation reactions are important for a wide variety of reasons, ranging from activation of steroid hormones in humans to the detoxification of compounds in the environment. The oxygenases we study contain a metal which is the key to the chemistry they catalyze. Enzyme mechanisms involve both the chemical reactions occurring at the active site and the regulation of the reaction imposed by the complex protein structure. Consequently, we use many types of biochemical and physical techniques including transient kinetics, site directed mutagenesis, diagnostic substrate reactions, and EPR spectroscopy. This is extended to X-ray crystallography and other spectroscopies through collaborations.
Currently, we are studying two large families of oxygenases. The first is typified by methane monooxygenases, the enzyme primarily responsible for preventing the vast amounts of biologically generated methane from reaching the atmosphere. This enzyme splits O2 and incorporates one atom of oxygen into methane to form methanol, while reducing the second atom to water. Another enzyme we have found from this family is essential for the biosynthesis of many important antibiotics and chemotherapy drugs. The second oxygenase family includes several dioxygenase enzymes that also split O2 but incorporate both atoms into biomolecules. These enzymes are the major means by which the enormous quantities of aromatic compounds that enter the environment annually are reassimilated into the carbon cycle. Recently, we have developed methods to trap reaction cycle intermediates of these enzymes in single crystals for direct structural analysis. Related collaborative projects include studies of the biosynthesis of biofuels, penicillin, fosfomycin, and ethylene (a plant hormone).
Banerjee, R., Proshlyakov, Y., Lipscomb, J.D., and Proshlyakov, D.A. “Structure of the key species in the enzymatic oxidation of methane to methanol” Nature, 518(7539), 431-434 (2015) PMC:4429310
Makris, T. M., Vu, V. V., Meier, K. K., Komor, A. J., Rivard, B. S., Münck, E., Que, L, Jr., and Lipscomb, J. D. “An Unusual Peroxo Intermediate of the Arylamine Oxygenase of the Chloramphenicol Biosynthetic Pathway”, J. Am. Chem. Soc., 137, 1608-1617 (2015) PMC:4318726
Knoot, C. J., Purpero, Vincent M., Lipscomb, J. D. “Crystal Structures of Alkylperoxo and Anhydride Intermediates in an Intradiol Ring-cleaving Dioxygenase” Proc. Natl. Acad. Sci., 112, 388-393 (2015) PMC:4299229
Lipscomb, J. D. “Life in a Sea of Oxygen” J. Biol. Chem. 289, 15141-15153 (2014) PMC: 4140874
Fielding, A. J., Lipscomb, J. D. and Que, L., Jr. “A Two-electron Shell Game: Intermediates of the Extradiol-cleaving Catechol Dioxygenases” J. Biol. Inorg. Chem., 19, 491-504 (2014) PMC:4039383
Makris, T. M., Knoot, C. J., Wilmot, C. M. and Lipscomb, J. D. “Structure of a Dinuclear Iron Cluster-Containing Beta Hydroxylase Active in Antibiotic Biosynthesis” Biochemistry, 52, 6662-6671 (2013) PMC: 3826434
Aukema, K. G., Makris, T. M., Stoian, S. A., Richman, J. E., Münck, E., Lipscomb, J. D., and Wackett L. P. “Cyanobacterial aldehyde deformylase oxygenation of fatty aldehydes yields n-1 aldehydes and alcohols in addition to fatty alkanes”, ACS Catalysis, 3, 2228–2238 (2013) PMC: 3903409
Banerjee, R., Meier, K. K., Münck, E., and Lipscomb, J. D. “Intermediate P* from Soluble Methane Monooxygenase Contains a Diferrous Cluster” Biochemistry, 52, 4331-4342 (2013) (Highlighted publication) PMC
Kovaleva, E. and Lipscomb, J. D. “Structural Basis for the Role of Tyrosine 257 of Homoprotocatechuate 2,3-Dioxygenase in Substrate and Oxygen Activation” Biochemistry, 51, 8755-8763 (2012) PMC
Mbughuni, M. M., Meier, K. K., Münck, E. and Lipscomb, J. D. “Substrate-Mediated Oxygen Activation by Homoprotocatechuate 2,3-Dioxygenase: Intermediates Formed by a Tyrosine 257 Variant” Biochemistry, 51, 8743-8754 (2012) PMC
Thompson, J. W., Salahudeen, A. A., Chollangi, S., Ruiz, J. C., Brautigam, C. A., Makris, T. M., Lipscomb, J. D., Tomchick, D. R., and Bruick, R. K. “Structural and Molecular Characterization of Iron-sensing Hemerythrin-like Domain within F-box and Leucine-rich Repeat Protein 5 (FBXL5)” J. Biol. Chem. 287, 7357-7365 (2012) (Cover illustration, paper of the year) PMC
Mbughuni, M. M., Chakrabarti, M., Hayden, J. A., Meier, K. K., Dalluge, J. J., Hendrich, M. P., Münck, E., and Lipscomb, J. D. “Oxy-Intermediates of Homoprotocatechuate 2,3-Dioxygenase: Facile Electron Transfer Between Substrates” Biochemistry, 50, 10262-10274 (2011) (Highlighted publication) PMC
Mbughuni, M. M., Chakrabarti, M., Hayden, J. A., Bominaar, E. L., Hendrich, M. P., Münck, E. and Lipscomb, J. D. “Trapping and Spectroscopic Characterization of an FeIII-Superoxo Intermediate from a Non-heme Mononuclear Iron-containing Enzyme” Proc. Natl. Acad. Sci. (U.S.A.), 107, 16788-16793 (2010) PMC
Makris, T. M., Chakrabarti, M., Münck, E. and Lipscomb, J. D. “A Family of Diiron Monooxygenases Catalyzing Amino Acid Beta Hydroxylation in Antibiotic Biosynthesis” Proc. Natl. Acad. Sci. (U.S.A.), 107 15391-15396 (2010) PMC