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High resolution XFEL structure of the soluble methane monooxygenase hydroxylase complex with its regulatory component at ambient temperature in two oxidation states

DOI: 10.1021/jacs.0c05613 DOI Help

Authors: Vivek Srinivas (Stockholm University) , Rahul Banerjee (University of Minnesota) , Hugo Lebrette (Stockholm University) , Jason C. Jones (University of Minnesota) , Oskar Aurelius (Stockholm University) , In-sik Kim (Lawrence Berkeley National Laboratory) , Cindy C. Pham (Lawrence Berkeley National Laboratory) , Sheraz Gul (Lawrence Berkeley National Laboratory) , Kyle Sutherlin (Lawrence Berkeley National Laboratory) , Asmit Bhowmick (Lawrence Berkeley National Laboratory) , Juliane John (Stockholm University) , Esra Bozkurt (Stockholm University) , Thomas Fransson (Lawrence Berkeley National Laboratory) , Pierre Aller (Diamond Light Source) , Agata Butryn (Diamond Light Source) , Isabel Bogacz (Lawrence Berkeley National Laboratory) , Philipp Stefan Simon (Lawrence Berkeley National Laboratory) , Stephen Keable (Lawrence Berkeley National Laboratory) , Alexander Britz (SLAC National Accelerator Laboratory) , Kensuke Tono (Japan Synchrotron Radiation Research Institute) , Kyung-sook Kim (Pohang Accelerator Laboratory) , Sang-youn Park (Pohang Accelerator Laboratory) , Sang-jae Lee (Pohang Accelerator Laboratory) , Jaehyun Park (Pohang Accelerator Laboratory) , Roberto Alonso-mori (SLAC National Accelerator Laboratory) , Franklin Fuller (SLAC National Accelerator Laboratory) , Alexander Batyuk (SLAC National Accelerator Laboratory) , Aaron S. Brewster (Lawrence Berkeley National Laboratory) , Uwe Bergmann (SLAC National Accelerator Laboratory) , Nicholas Sauter (Lawrence Berkeley National Laboratory) , Allen M. Orville (Diamond Light Source; Research Complex at Harwell) , Vittal K. Yachandra (Lawrence Berkeley National Laboratory) , Junko Yano (Lawrence Berkeley National Laboratory) , John D. Lipscomb (University of Minnesota) , Jan F. Kern (Lawrence Berkeley National Laboratory) , Martin Högbom (Stockholm University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The American Chemical Society

State: Published (Approved)
Published: July 2020

Abstract: Soluble methane monooxygenase (sMMO) is a multicomponent metalloenzyme that catalyzes the conversion of methane to methanol at ambient temperature using a nonheme, oxygen-bridged dinuclear iron cluster in the active site. Structural changes in the hydroxylase component (sMMOH) containing the diiron cluster caused by complex formation with a regulatory component (MMOB) and by iron reduction are important for the regulation of O2 activation and substrate hydroxylation. Structural studies of metalloenzymes using traditional synchrotron-based X-ray crystallography are often complicated by partial X-ray-induced photoreduction of the metal center, thereby obviating determination of the structure of pure oxidation states. Here microcrystals of the sMMOH:MMOB complex from Methylosinus trichosporium OB3b were serially exposed to X-ray free electron laser (XFEL) pulses, where the ≦35 fs duration of exposure of an individual crystal yields diffraction data before photoreduction-induced structural changes can manifest. Merging diffraction patterns obtained from thousands of crystals generates radiation damage free, 1.95 Å resolution crystal structures for the fully oxidized and fully reduced states of the sMMOH:MMOB complex for the first time. The results provide new insight into the manner by which the diiron cluster and the active site environment are reorganized by the regulatory protein component in order to enhance the steps of oxygen activation and methane oxidation. This study also emphasizes the value of XFEL and serial femtosecond crystallography (SFX) methods for investigating the structures of metalloenzymes with radiation sensitive metal active sites.

Subject Areas: Chemistry

Facility: ESRF; Swiss Light Source; LCLS/SLAC; SACLA