title: Redox-dependent structural changes in archaeal and bacterial Rieske-type [2Fe-2S] clusters.
abstract: Proteins containing Rieske-type [2Fe-2S] clusters play important roles in many biological electron transfer reactions. Typically, [2Fe-2S] clusters are not directly involved in the catalytic transformation of substrate, but rather supply electrons to the active site. We report herein X-ray absorption spectroscopic (XAS) data that directly demonstrate an average increase in the iron-histidine bond length of at least 0.1 A upon reduction of two distantly related Rieske-type clusters in archaeal Rieske ferredoxin from Sulfolobus solfataricus strain P-1 and bacterial anthranilate dioxygenases from Acinetobacter sp. strain ADP1. This localized redox-dependent structural change may fine tune the protein-protein interaction (in the case of ARF) or the interdomain interaction (in AntDO) to facilitate rapid electron transfer between a lower potential Rieske-type cluster and its redox partners, thereby regulating overall oxygenase reactions in the cells.
authors.affiliation: Center for Metalloenzyme Studies, University of Georgia, Athens 30602, USA. ncosper@uga.edu
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Cosper
authors.forename: D Matthew
authors.initials: DM
authors.lastname: Eby
authors.forename: Asako
authors.initials: A
authors.lastname: Kounosu
authors.forename: Norio
authors.initials: N
authors.lastname: Kurosawa
authors.forename: Ellen L
authors.initials: EL
authors.lastname: Neidle
authors.forename: Donald M
authors.initials: DM
authors.lastname: Kurtz
authors.forename: Toshio
authors.initials: T
authors.lastname: Iwasaki
authors.forename: Robert A
authors.initials: RA
authors.lastname: Scott
mesh_terms: D000150:Acinetobacter / Q000737:chemistry; D019843:Archaeal Proteins / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D004579:Electron Transport; D014450:Electron Transport Complex III; D005288:Ferredoxins / Q000737:chemistry; D005583:Fourier Analysis; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary; D016944:Sulfolobus / Q000737:chemistry
chemical_list: D019843:Archaeal Proteins; D001426:Bacterial Proteins; D005288:Ferredoxins; D007506:Iron-Sulfur Proteins; C037989:Rieske iron-sulfur protein; D014450:Electron Transport Complex III