The Photoactive Excited State of the B12-Based Photoreceptor CarH
| العنوان: | The Photoactive Excited State of the B12-Based Photoreceptor CarH |
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| المؤلفون: | Joseph H Meadows, Aniruddha Deb, Roseanne J. Sension, Alexander Britz, Tim Brandt van Driel, Nicholas A. Miller, Roberto Alonso-Mori, Arkaprabha Konar, Kevin J. Kubarych, Leena Mallik, James M. Glownia, April K Kaneshiro, Subramanian Padmanabhan, E. Neil G. Marsh, James E. Penner-Hahn, Jake Koralek, Markos Koutmos, Montserrat Elías-Arnanz, Lindsay B Michocki |
| المساهمون: | National Science Foundation (US), Ministerio de Ciencia, Innovación y Universidades (España), Fundación Séneca, Department of Energy (US) |
| المصدر: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| بيانات النشر: | American Chemical Society, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | Materials science, 010304 chemical physics, Quantum yield, 010402 general chemistry, Photochemistry, 01 natural sciences, Adenosylcobalamin, 0104 chemical sciences, Surfaces, Coatings and Films, Homolysis, Excited state, 0103 physical sciences, Ultrafast laser spectroscopy, Materials Chemistry, medicine, Quantum efficiency, Physical and Theoretical Chemistry, Spectroscopy, Excitation, medicine.drug |
| الوصف: | 7 pags., 5 figs. We have used transient absorption spectroscopy in the UV-visible and X-ray regions to characterize the excited state of CarH, a protein photoreceptor that uses a form of B12, adenosylcobalamin (AdoCbl), to sense light. With visible excitation, a nanosecond-lifetime photoactive excited state is formed with unit quantum yield. The time-resolved X-ray absorption near edge structure difference spectrum of this state demonstrates that the excited state of AdoCbl in CarH undergoes only modest structural expansion around the central cobalt, a behavior similar to that observed for methylcobalamin rather than for AdoCbl free in solution. We propose a new mechanism for CarH photoreactivity involving formation of a triplet excited state. This allows the sensor to operate with high quantum efficiency and without formation of potentially dangerous side products. By stabilizing the excited electronic state, CarH controls reactivity of AdoCbl and enables slow reactions that yield nonreactive products and bypass bond homolysis and reactive radical species formation. This work was supported by grants from the National Science Foundation NSF-CHE 1464584 and NSFCHE 1836435 to R.J.S., NSF-CHE 1565795 to K.J.K., NSFCHE 1608553 and NSF-CHE-1904759 to E.N.G.M., and NSF-CHE 1945174 to M.K.; from the Agencia Estatal de Investigación (AEI)-Spain and the European Regional Development Fund (FEDER) grants PGC2018-094635-BC21 (to M.E.-A.) and PGC2018-094635-B-C22 (to S.P.); and from the Fundacion Seneca (Murcia)-Spain grant 20992/PI/ ́ 18 (to M.E.-A.). Portions of this work were carried out in the Laboratory for Ultrafast Multidimensional Optical Spectroscopy (LUMOS) supported by NSF-CHE 1428479. Use of the Linac Coherent Light Source (LCLS), SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-76SF00515. |
| تدمد: | 1520-5207 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::eaa43d637e5f94a2ef87db88d01840ca http://hdl.handle.net/10261/229423 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....eaa43d637e5f94a2ef87db88d01840ca |
| قاعدة البيانات: | OpenAIRE |
Find this issue from the American Chemical Society | تدمد: | 15205207 |
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