title: Complex formation between protoporphyrinogen IX oxidase and ferrochelatase during haem biosynthesis in Thermosynechococcus elongatus.
abstract: During haem and chlorophyll biosynthesis, flavin-dependent protoporphyrinogen IX oxidase catalyses the six-electron oxidation of protoporphyrinogen IX to form protoporphyrin IX. In the following step, iron is inserted into protoporphyrin IX by ferrochelatase. Based on the solved crystal structures of these enzymes, an in silico model for a complex between these two enzymes was proposed to protect the highly photoreactive intermediate protoporphyrin IX. The existence of this complex was verified by two independent techniques. First, co-immunoprecipitation experiments using antibodies directed against recombinantly produced and purified Thermosynechococcus elongatus protoporphyrinogen IX oxidase and ferrochelatase demonstrated their physical interaction. Secondly, protein complex formation was visualized by in vivo immunogold labelling and electron microscopy with T. elongatus cells. Finally, oxygen-dependent coproporphyrinogen III oxidase, which catalyses the formation of protoporphyrinogen IX, was not found to be part of this complex when analysed with the same methodology.
authors.affiliation: Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
authors.forename: Ava
authors.initials: A
authors.lastname: Masoumi
authors.affiliation: Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
authors.forename: Ilka Ursula
authors.initials: IU
authors.lastname: Heinemann
authors.affiliation: Division of Microbiology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, D-38124 Braunschweig, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Rohde
authors.affiliation: Laboratoire de Biologie et de Génomique Structurales, IGBMC, Parc d'Innovation, 1 rue Laurent Fries, BP 10142, F-67404 Illkirch Cedex, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Koch
authors.affiliation: Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Jahn
authors.affiliation: Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Jahn
mesh_terms: D003304:Coproporphyrinogen Oxidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000458:Cyanobacteria / Q000201:enzymology* / Q000378:metabolism; D005294:Ferrochelatase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006418:Heme / Q000096:biosynthesis*; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D008854:Microscopy, Electron; D008958:Models, Molecular; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism*; D050768:Protoporphyrinogen Oxidase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011524:Protoporphyrins / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D011524:Protoporphyrins; D006418:Heme; C011539:protoporphyrinogen; D003304:Coproporphyrinogen Oxidase; D050768:Protoporphyrinogen Oxidase; D005294:Ferrochelatase