Wheat mitochondria ccmB encodes the membrane domain of a putative ABC transporter involved in cytochrome c biogenesis.
Assembly of cytochromes c is mediated by different proteins depending on the organism and organelle considered. In land plants, mitochondria follow a pathway distinct from that of yeast and animal mitochondria, more similar to that described for alpha- and gamma-proteobacteria. Indeed, in plant mitochondria, four genes were identified based on the similarities of their products with bacterial proteins involved in c-type cytochrome maturation. We report the characterisation of one of these mitochondrial genes in Triticum aestivum, TaccmB, which is proposed to encode a subunit of an ABC transporter. The transcript extremities were mapped and cDNA sequencing revealed 42 C to U editing positions in the 618 nucleotide long coding region. This high editing rate affects the identity of 32 amino acids out of 206. Antibodies directed against wheat CcmB recognise a 28 kDa protein in an enriched inner mitochondrial membrane protein fraction, a location which is in agreement with the high hydrophobicity of the protein and its function as a putative transmembrane domain of an ABC transporter involved in cytochrome c and c1 biogenesis in plant mitochondria.
Faivre-Nitschke
S E
SE
Institut de Biologie Moléculaire des Plantes du CNRS, Université Louis Pasteur, 12 rue du Général Zimmer, F-67084 Cedex, Strasbourg, France.
Nazoa
P
P
Gualberto
J M
JM
Grienenberger
J M
JM
Bonnard
G
G
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D001483:Base Sequence; D003574:Cytochrome c Group / Q000378:metabolism*; D018076:DNA, Complementary; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008928:Mitochondria / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D010940:Plant Proteins; D017393:RNA Editing; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014908:Triticum / Q000235:genetics*
D018528:ATP-Binding Cassette Transporters; C432130:CcmB protein, Triticum aestivum; D003574:Cytochrome c Group; D018076:DNA, Complementary; D008565:Membrane Proteins; D010940:Plant Proteins; D012333:RNA, Messenger