The maxicircle of Trypanosoma brucei kinetoplast DNA encodes apocytochrome b

The region of the maxicircle of Trypanosoma brucei kinetoplast DNA which hybridizes at low stringency with the apocytochrome b gene of Saccharomyces cerevisiae has been identified and cloned. The nucleotide sequence of a 1.7 kb segment of this region is reported. This segment contains a single long open reading from capable of coding for a 350 amino acid protein with substantial homology to apocytochromes b of other species. The trypanosome protein is considerably more distantly related to other apocytochromes b than they are to each other. Several short unassigned open reading frames (300 nucleotides or shorter) also are described. If polypeptides are synthesized from these regions, they are more hydrophilic than known mitochondrially coded proteins.