Iron–sulfur proteins in plant mitochondria: roles and maturation
Résumé
Abstract Iron–sulfur (Fe–S) clusters are prosthetic groups ensuring electron transfer reactions, activating substrates for catalytic reactions, providing sulfur atoms for the biosynthesis of vitamins or other cofactors, or having protein-stabilizing effects. Hence, metalloproteins containing these cofactors are essential for numerous and diverse metabolic pathways and cellular processes occurring in the cytoplasm. Mitochondria are organelles where the Fe–S cluster demand is high, notably because the activity of the respiratory chain complexes I, II, and III relies on the correct assembly and functioning of Fe–S proteins. Several other proteins or complexes present in the matrix require Fe–S clusters as well, or depend either on Fe–S proteins such as ferredoxins or on cofactors such as lipoic acid or biotin whose synthesis relies on Fe–S proteins. In this review, we have listed and discussed the Fe–S-dependent enzymes or pathways in plant mitochondria including some potentially novel Fe–S proteins identified based on in silico analysis or on recent evidence obtained in non-plant organisms. We also provide information about recent developments concerning the molecular mechanisms involved in Fe–S cluster synthesis and trafficking steps of these cofactors from maturation factors to client apoproteins.