3VCA

Quaternary Ammonium Oxidative Demethylation: X-ray Crystallographic, Resonance Raman and UV-visible Spectroscopic Analysis of a Rieske-type Demethylase

Summary for 3VCA

• Entry DOI: 10.2210/pdb3vca/pdb
• Related: 3VCP
• Descriptor: Ring-hydroxylating dioxygenase, FE2/S2 (INORGANIC) CLUSTER, FE (III) ION, ... (6 entities in total)
• Functional Keywords: rieske-type, mononuclear non-heme iron, n-demethylase, oxidoreductase
• Biological source: Sinorhizobium meliloti (Ensifer meliloti)
• Total number of polymer chains: 1
• Total formula weight: 46864.35

Authors

Daughtry, K.D.,Xiao, Y.,Stoner-Ma, D.,Cho, E.,Orville, A.M.,Liu, P.,Allen, K.N. (deposition date: 2012-01-03, release date: 2012-02-08, Last modification date: 2024-10-30)

Primary citation

Daughtry, K.D.,Xiao, Y.,Stoner-Ma, D.,Cho, E.,Orville, A.M.,Liu, P.,Allen, K.N.
Quaternary Ammonium Oxidative Demethylation: X-ray Crystallographic, Resonance Raman, and UV-Visible Spectroscopic Analysis of a Rieske-Type Demethylase.
J.Am.Chem.Soc., 134:2823-2834, 2012

PubMed 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.

PubMed: 22224443
DOI: 10.1021/ja2111898

Experimental method

X-RAY DIFFRACTION (1.59 Å)