Nucleotide Sequence of a cDNA Encoding the ADP/ATP Carrier from Wheat (Triticum turgidum)

The adenine nucleotide carrier is the most abundant mitochondrial membrane protein. It catalyzes the exchange of adenine nucleotides between mitochondrial matrix and cytosol and plays a central role in the integration of mitochondrial metabolism. We have characterized an ADP/ ATP carrier cDNA from wheat (Triticum turgidum) with a view toward gaining an understanding of the expression and biogenesis of this protein in higher plants. The cDNA sequence has been obtained from a wheat single-stranded cDNA by PCR utilizing sequence information from the Zea mays homolog (Bathgate et al., 1989). Overlapping cDNA fragments were obtained. To extend the sequence to the 5’ end a modified cDNA tailed with a poly(A) was used. The cDNA of the ADP/ATP carrier is 1035 bp in length. The open reading frame encodes the mature protein consisting of 331 amino acids (Table I). The amino acid sequence of the wheat ADP/ATP carrier is 90.3 and 79.6% identical to that of the ADP/ATP carrier from maize (Bathgate et al., 1989) and rice (Hashimoto et al., 1993). Most of the differences are located at the N-terminal region. Since the function of this region is not known, the significance of these differences is not understood.