Nuclear Resonance Vibrational Spectroscopic Definition of Peroxy Intermediates in Nonheme Iron Sites

Journal Article · 02 November 2016 · Journal of the American Chemical Society

DOI: https://doi.org/10.1021/jacs.6b07227 · OSTI ID:1360201

Sutherlin, Kyle D. ^[1]; Liu, Lei V. ^[1]; Lee, Yong-Min ^[2]; Kwak, Yeonju ^[1]; Yoda, Yoshitaka ^[3]; Saito, Makina ^[4]; Kurokuzu, Masayuki ^[4]; Kobayashi, Yasuhiro ^[4]; Seto, Makoto ^[4]; Que, Lawrence ^[5]; Nam, Wonwoo ^[2]; Solomon, Edward I. ^[6]

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1. Stanford Univ., CA (United States). Dept. of Chemistry
2. Ewha Womans Univ., Seoul (Korea). Center for Biomimetic Systems, Dept. of Bioinspired Science, Dept. of Chemistry and Nano Science
3. Japan Synchrotron Radiation Research Inst. (JASRI), Hyogo (Japan). SPring-8
4. Kyoto Univ., Osaka (Japan). Research Reactor Inst.
5. Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemistry
6. Stanford Univ., CA (United States). Dept. of Chemistry; SLAC National Accelerator Lab., Menlo Park, CA (United States)

Fe^III-(hydro)peroxy intermediates have been isolated in two classes of mononuclear nonheme Fe enzymes that are important in bioremediation: the Rieske dioxygenases and the extradiol dioxygenases. The binding mode and protonation state of the peroxide moieties in these intermediates are not well-defined, due to a lack of vibrational structural data. Nuclear resonance vibrational spectroscopy (NRVS) is an important technique for obtaining vibrational information on these and other intermediates, as it is sensitive to all normal modes with Fe displacement. Here in this paper, we present the NRVS spectra of side-on Fe^III-peroxy and end-on Fe^III-hydroperoxy model complexes and assign these spectra using calibrated DFT calculations. We then use DFT calculations to define and understand the changes in the NRVS spectra that arise from protonation and from opening the Fe–O–O angle. This study identifies four spectroscopic handles that will enable definition of the binding mode and protonation state of Fe^III-peroxy intermediates in mononuclear nonheme Fe enzymes. These structural differences are important in determining the frontier molecular orbitals available for reactivity.

• Research Organization: SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE; National Institutes of Health (NIH); National Research Foundation of Korea (NRF); Japan Society for the Promotion of Science (JSPS); National Science Foundation (NSF)
• Grant/Contract Number: AC02-76SF00515; CHE-1361773; NRF-2010-00353; NRF-2012R1A3A2048842; 24221005; GM-40392
• OSTI ID: 1360201
• Journal Information: Journal of the American Chemical Society, Vol. 138, Issue 43; ISSN 0002-7863
• Publisher: American Chemical Society (ACS)Copyright Statement
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY