tailieunhanh - Báo cáo khoa học: Structure of coenzyme F420H2 oxidase (FprA), a di-iron flavoprotein from methanogenic Archaea catalyzing the reduction of O2 to H2O

The di-iron flavoprotein F420H2 oxidase found in methanogenic Archaea catalyzes the four-electron reduction of O2to 2H2O with 2 mol of reduced coenzyme F420(7,8-dimethyl-8-hydroxy-5-deazariboflavin). We report here on crystal structures of the homotetrameric F420H2 oxidase fromMethan-othermobacter marburgensis at resolutions of A ˚ , A ˚ and A ˚ , respectively, from which an active reduced state, an inactive oxidized state and an active oxidized state could be extracted. | ễFEBS Journal Structure of coenzyme F42qH2 oxidase FprA a di-iron flavoprotein from methanogenic Archaea catalyzing the reduction of O2 to H2O Henning Seedorf1 Christoph H. Hagemeier1 Seigo Shima1 Rudolf K. Thauer1 Eberhard Warkentin2 and Ulrich Ermler2 1 Max Planck Institute for TerrestrialMicrobiology Marburg Germany 2 Max Planck Institute for Biophysics Frankfurt am Main Germany Keywords coenzyme F420 crystal structure di-iron center F420H2 oxidase O2 detoxification Correspondence U. Ermler Max Planck Institute for Biophysics Max-von-Laue-Str. 3 D-60438 Frankfurt am Main Germany Fax 49 69 63031002 Tel 49 69 63031054 E-mail Received 14 November 2006 revised 11 January 2007 accepted 17 January 2007 doi The di-iron flavoprotein F420H2 oxidase found in methanogenic Archaea catalyzes the four-electron reduction of O2 to 2H2O with 2 mol of reduced coenzyme F420 7 8-dimethyl-8-hydroxy-5-deazariboflavin . We report here on crystal structures of the homotetrameric F420H2 oxidase from Methan-othermobacter marburgensis at resolutions of A A and A respectively from which an active reduced state an inactive oxidized state and an active oxidized state could be extracted. As found in structurally related A-type flavoproteins the active site is formed at the dimer interface where the di-iron center of one monomer is juxtaposed to FMN of the other. In the active reduced state Fe II Fe II FMNH2 the two irons are surrounded by four histidines one aspartate one glutamate and one bridging aspartate. The so-called switch loop is in a closed conformation thus preventing F420 binding. In the inactive oxidized state Fe III FMN the iron nearest to FMN has moved to two remote binding sites and the switch loop is changed to an open conformation. In the active oxidized state Fe III Fe III FMN both irons are positioned as in the reduced state but the switch loop is found in the open conformation as in the .