Complex formation between protoporphyrinogen IX oxidase and ferrochelatase during haem biosynthesis in Thermosynechococcus elongatus.
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.
Masoumi
Ava
A
Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
Heinemann
Ilka Ursula
IU
Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
Rohde
Manfred
M
Division of Microbiology, Helmholtz Centre for Infection Research (HZI), Inhoffenstr. 7, D-38124 Braunschweig, Germany.
Koch
Michael
M
Laboratoire de Biologie et de Génomique Structurales, IGBMC, Parc d'Innovation, 1 rue Laurent Fries, BP 10142, F-67404 Illkirch Cedex, France.
Jahn
Martina
M
Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
Jahn
Dieter
D
Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany.
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
D009097:Multienzyme Complexes; D011524:Protoporphyrins; D006418:Heme; C011539:protoporphyrinogen; D003304:Coproporphyrinogen Oxidase; D050768:Protoporphyrinogen Oxidase; D005294:Ferrochelatase