The N- and C-termini of the tricarboxylate carrier are exposed to the cytoplasmic side of the inner mitochondrial membrane.
Polyclonal antibodies were raised in rabbits against two synthetic peptides corresponding to the N- and C-terminal regions of the rat-liver mitochondrial tricarboxylate carrier. ELISA tests performed with intact and permeabilized rat-liver mitoplasts showed that both anti-N-terminal and anti-C-terminal antibodies bind only to the cytoplasmic surface of the inner membrane, indicating that both termini of the membrane-bound tricarboxylate carrier are exposed to the mitochondrial intermembrane space. Furthermore, tryptic digestion of intact mitoplasts markedly decreased the binding of anti-N-terminal and anti-C-terminal antibodies to the tricarboxylate carrier. These results are consistent with an arrangement of the tricarboxylate carrier monomer into an even number of transmembrane segments, with the N- and C-termini protruding toward the cytosol.
Capobianco
L
L
Department of Pharmaco-Biology, University of Bari, Italy.
Bisaccia
F
F
Michel
A
A
Sluse
F E
FE
Palmieri
F
F
D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism*; D008969:Molecular Sequence Data; D051381:Rats
D002352:Carrier Proteins; C020723:citrate-binding transport protein