BIOCHEMICAL AND MOLECULAR-GENETIC PROPERTIES OF A CYTOCHROME-C-DEFICIENT MUTANT OF KLUYVEROMYCES-LACTIS

We have isolated a respiration-deficient nuclear mutant of the yeast K luyveromyces lactis that exhibited diminished levels of all cytochrome s and did not grow on glycerol and other nonfermentable carbon sources . The mutant named cyc1 was transformed with a K. lactis genomic libra ry and the DNA fragment conferring its wild-type properties was isolat ed and sequenced. The sequence of the isolated gene showed extensive h omology with other eukaryotic cytochrome-c genes. The highest level of homology, based on the deduced amino acid sequences, was observed bet ween the gene products of K. lactis and Hansenula anomala.