Quaternary Ammonium Oxidative Demethylation: X-ray Crystallographic, Resonance Raman, and UV–Visible Spectroscopic Analysis of a Rieske-Type Demethylase
- 8 January 2012
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 134 (5), 2823-2834
- https://doi.org/10.1021/ja2111898
Abstract
Herein, the structure resulting from in situ turnover in a chemically challenging quaternary ammonium oxidative demethylation reaction was captured via crystallographic analysis and analyzed via single-crystal spectroscopy. Crystal structures were determined for the Rieske-type monooxygenase, stachydrine demethylase, in the unliganded state (at 1.6 Å resolution) and in the product complex (at 2.2 Å resolution). The ligand complex was obtained from enzyme aerobically cocrystallized with the substrate stachydrine (N,N-dimethylproline). The ligand electron density in the complex was interpreted as proline, generated within the active site at 100 K by the absorption of X-ray photon energy and two consecutive demethylation cycles. The oxidation state of the Rieske iron–sulfur cluster was characterized by UV–visible spectroscopy throughout X-ray data collection in conjunction with resonance Raman spectra collected before and after diffraction data. Shifts in the absorption band wavelength and intensity as a function of absorbed X-ray dose demonstrated that the Rieske center was reduced by solvated electrons generated by X-ray photons; the kinetics of the reduction process differed dramatically for the liganded complex compared to unliganded demethylase, which may correspond to the observed turnover in the crystal.This publication has 100 references indexed in Scilit:
- Synchrotron X-ray-Induced Photoreduction of Ferric Myoglobin Nitrite Crystals Gives the Ferrous Derivative with Retention of the O-Bonded Nitrite LigandBiochemistry, 2010
- Crystal Structure of Dicamba Monooxygenase: A Rieske Nonheme Oxygenase that Catalyzes Oxidative DemethylationJournal of Molecular Biology, 2009
- Crystallographic, Spectroscopic, and Computational Analysis of a Flavin C4a−Oxygen Adduct in Choline Oxidase,Biochemistry, 2009
- Similar enzymes, different structures: Phthalate dioxygenase is an α3α3 stacked hexamer, not an α3β3 trimer like “normal” Rieske oxygenasesArchives of Biochemistry and Biophysics, 2007
- Inference of Macromolecular Assemblies from Crystalline StateJournal of Molecular Biology, 2007
- The catalytic pocket of the ring-hydroxylating dioxygenase from Sphingomonas CHY-1Biochemical and Biophysical Research Communications, 2007
- The Cryo-EM Structure of a Translation Initiation Complex from Escherichia coliCell, 2005
- Histone Demethylation Mediated by the Nuclear Amine Oxidase Homolog LSD1Cell, 2004
- ARP⧸wARP and Automatic Interpretation of Protein Electron Density MapsMethods in Enzymology, 2003
- [20] Processing of X-ray diffraction data collected in oscillation modeMethods in Enzymology, 1997