Immunological identification of the alternative oxidase in Chlamydomonas reinhardtii (Chlorophyta)

Using a monoclonal antibody to the alternative oxidase from voodoo lily, we provide evidence that the green alga Chlamydomonas reinhardtii Dang. possesses a protein that is immunologically related to the higher plant alternative oxidase. Mitochondria were isolated from a cell wall-less mutant strain (CW-15), and the presence of cyanide-resistant oxygen consumption was confined in these mitochondria. The voodoo lily antibody was used as a probe for immunoblotting of sodium dodecyl sulphate-polyacrylamide gel electrophoresis gels of mitochondrial proteins of C. reinhardtii. The antibody reacted with a protein from C. reinhardtii with the same molecular mass (36 kDa) as the alternative oxidase form voodoo lily and tobacco mitochondria. These results suggest that cyanide-resistant respiration in C. reinhardtii is mediated by a higher plant-type alternative oxidase.