INVESTIGADORES
GOMEZ CASATI Diego Fabian
congresos y reuniones científicas
Título:
Frataxin as the source of ferrochelatase activity in plant mitochondria.
Autor/es:
ARMAS, ALEJANDRO M.; TERENZI, AGUSTINA; BUSI, MARIA VICTORIA; PAGANI M.A.; DIEGO FABIAN GOMEZ CASATI
Lugar:
Aguas de Lindoia
Reunión:
Congreso; 48a Reunion anual de la Sociedade Brasileira de Bioquimica e Biologia Molecular (SBBq),; 2019
Institución organizadora:
Sociedade Brasileira de Bioquimica e Biologia Molecular (SBBq),
Resumen:
INTRODUCTION: Frataxinplays a key role in cellular ironhomeostasis of different organisms. It is engaged in several activities at theFe-S cluster assembly machinery and it isalso involved in heme biosynthesis. In plants, two genes encodingferrochelatases (FC1 and FC2) catalyze the incorporation of iron intoprotoporphyrin IX in the last stage of heme synthesis in chloroplasts. Despite ferrochelatases are absent from othercell compartments, ferrochelatase activity hasbeen observed in plant mitochondria. OBJECTIVES: Herewe analyze the possibility that frataxin acts as the iron donor toprotoporphyrin IX for the synthesis of heme groups in plant mitochondria as analternative to the regular chloroplastic pathway. MATERIALS AND METHODS: We expressed and purified theproteins frataxin, AtNFS1, and AtISD11 to study their ability to form heme in vitro. The products in the reactionmix were analyzed by thin layer chromatography. Heme content and catalaseactivity were measured in AtNFS1overexpressing and knockdown mutant Arabidopsis plants. DISCUSSION AND RESULTS:Our findingsshow that frataxin catalyzes the formation of heme in vitro when it is incubatedwith iron and protoporphyrin IX. When frataxin is combined with AtNFS1 andAtISD11 the ferrochelatase activity is increased suggesting that a proteincomplex is formed that regulates the activity of both AtNFS1 and frataxin. AtNFS1 overexpressing and mutant plantsshowed alterations in the heme content and in the catalase activity. CONCLUTION: These results suggest thatfrataxin could be the iron donor in the final step of heme synthesis in plantmitochondria, and constitutes an importantadvance in the elucidation of themechanisms of heme synthesis in plants.
