Subcellular localization studies on the electron transfer components comprising of an adrenocortical ferredoxin homologue and its oxidoreductase in Arabidopsis

Abstract

Among a number of potential ferredoxin reductase genes in Arabidopsis genome, we have identified AtMFDR to correspond to a homologue of adrenodoxin reductase (mitochondrial ferredoxin reductase), and AtMFDX1 and AtMFDX2 as the genes for ferredoxins similar to adrenodoxin (mitochondrial ferredoxin). The deduced primary structures of AtMFDR and AtMFDXs contained the signature sequences involved in the electron transfer, and the recombinant AtMFDX1 and AtMFDR proteins were fully active to reconstitute the electron-transfer activity with NAD(P)H as the electron donor. Protein-gel blot analysis indicated constant accumulation of AtMFDR protein in leaf, stem, and flower. Subcellular fractionation analysis demonstrated membrane association of AtMFDR protein, and immunohistochemical studies revealed specific structure for the AtMFDR localization. Detailed analysis is in progress to clarify the membrane structure where the proteins exert their physiological functions.