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Stepwise Hydride Transfer in a Biological System: Insights into the Reaction Mechanism of the Light-Dependent Protochlorophyllide Oxidoreductase.
- Source :
-
Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2018 Mar 01; Vol. 57 (10), pp. 2682-2686. Date of Electronic Publication: 2018 Feb 05. - Publication Year :
- 2018
-
Abstract
- Hydride transfer plays a crucial role in a wide range of biological systems. However, its mode of action (concerted or stepwise) is still under debate. Light-dependent NADPH: protochlorophyllide oxidoreductase (POR) catalyzes the stereospecific trans addition of a hydride anion and a proton across the C <subscript>17</subscript> -C <subscript>18</subscript> double bond of protochlorophyllide. Time-resolved absorption and emission spectroscopy were used to investigate the hydride transfer mechanism in POR. Apart from excited states of protochlorophyllide, three discrete intermediates were resolved, consistent with a stepwise mechanism that involves an initial electron transfer from NADPH. A subsequent proton-coupled electron transfer followed by a proton transfer yield distinct different intermediates for wild type and the C226S variant, that is, initial hydride attaches to either C <subscript>17</subscript> or C <subscript>18</subscript> , but ends in the same chlorophyllide stereoisomer. This work provides the first evidence of a stepwise hydride transfer in a biological system.<br /> (© 2018 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.)
Details
- Language :
- English
- ISSN :
- 1521-3773
- Volume :
- 57
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Angewandte Chemie (International ed. in English)
- Publication Type :
- Academic Journal
- Accession number :
- 29363234
- Full Text :
- https://doi.org/10.1002/anie.201712729