@article{cha_milikisiyants_davidson_xue_smirnova_smirnov_guo_chang_2020, title={Alternative Reactivity of Leucine 5-Hydroxylase Using an Olefin-Containing Substrate to Construct a Substituted Piperidine Ring}, volume={59}, ISSN={["0006-2960"]}, url={https://doi.org/10.1021/acs.biochem.0c00289}, DOI={10.1021/acs.biochem.0c00289}, abstractNote={Applying enzymatic reactions to produce useful molecules is a central focus of chemical biology. Iron and 2-oxoglutarate (Fe/2OG) enzymes are found in all kingdoms of life and catalyze a broad array of oxidative transformations. Herein, we demonstrate that the activity of an Fe/2OG enzyme can be redirected when changing the targeted carbon hybridization from sp3 to sp2. During leucine 5-hydroxylase catalysis, installation of an olefin group onto the substrate redirects the Fe(IV)-oxo species reactivity from hydroxylation to asymmetric epoxidation. The resulting epoxide subsequently undergoes intramolecular cyclization to form the substituted piperidine, 2S,5S-hydroxypipecolic acid.}, number={21}, journal={BIOCHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Cha, Lide and Milikisiyants, Sergey and Davidson, Madison and Xue, Shan and Smirnova, Tatyana I and Smirnov, Alex I and Guo, Yisong and Chang, Wei-Chen}, year={2020}, month={Jun}, pages={1961–1965} }
 @article{davidson_mcnamee_fan_guo_chang_2019, title={Repurposing Nonheme Iron Hydroxylases To Enable Catalytic Nitrile Installation through an Azido Group Assistance}, volume={141}, ISSN={["0002-7863"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85062294563&partnerID=MN8TOARS}, DOI={10.1021/jacs.8b13906}, abstractNote={Three mononuclear nonheme iron and 2-oxoglutarate dependent enzymes, l-Ile 4-hydroxylase, l-Leu 5-hydroxylase and polyoxin dihydroxylase, are previously reported to catalyze the hydroxylation of l-isoleucine, l-leucine, and l-α-amino-δ-carbamoylhydroxyvaleric acid (ACV). In this study, we showed that these enzymes can accommodate leucine isomers and catalyze regiospecific hydroxylation. On the basis of these results, as a proof-of-concept, we demonstrated that the outcome of the reaction can be redirected by installation of an assisting group within the substrate. Specifically, instead of canonical hydroxylation, these enzymes can catalyze non-native nitrile group installation when an azido group is introduced. The reaction is likely to proceed through C—H bond activation by an Fe(IV)-oxo species, followed by azido-directed C≡N bond formation. These results offer a unique opportunity to investigate and expand the reaction repertoire of Fe/2OG enzymes.}, number={8}, journal={JOURNAL OF THE AMERICAN CHEMICAL SOCIETY}, author={Davidson, Madison and McNamee, Meredith and Fan, Ruixi and Guo, Yisong and Chang, Wei-chen}, year={2019}, month={Feb}, pages={3419–3423} }
 @article{liao_li_huang_davidson_kurnikov_lin_lee_kurnikova_guo_chan_et al._2018, title={Insights into the Desaturation of Cyclopeptin and its C3 Epimer Catalyzed by a non-Heme Iron Enzyme: Structural Characterization and Mechanism Elucidation}, volume={57}, ISSN={["1521-3773"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85040694556&partnerID=MN8TOARS}, DOI={10.1002/anie.201710567}, abstractNote={AsqJ, an iron(II)- and 2-oxoglutarate-dependent enzyme found in viridicatin-type alkaloid biosynthetic pathways, catalyzes sequential desaturation and epoxidation to produce cyclopenins. Crystal structures of AsqJ bound to cyclopeptin and its C3 epimer are reported. Meanwhile, a detailed mechanistic study was carried out to decipher the desaturation mechanism. These findings suggest that a pathway involving hydrogen atom abstraction at the C10 position of the substrate by a short-lived FeIV -oxo species and the subsequent formation of a carbocation or a hydroxylated intermediate is preferred during AsqJ-catalyzed desaturation.}, number={7}, journal={ANGEWANDTE CHEMIE-INTERNATIONAL EDITION}, author={Liao, Hsuan-Jen and Li, Jikun and Huang, Jhih-Liang and Davidson, Madison and Kurnikov, Igor and Lin, Te-Sheng and Lee, Justin L. and Kurnikova, Maria and Guo, Yisong and Chan, Nei-Li and et al.}, year={2018}, month={Feb}, pages={1831–1835} }