STRUCTURE OF THE ABF1-HOMOLOG FROM KLUYVEROMYCES-MARXIANUS

By transformation of a Saccharomyces cerevisiae mutant strain conditio nally expressing the ABF1-gene, a Kluyveromyces marxianus DNA fragment carrying the gene encoding the ABF1-homologue of this yeast strain (K mABF1) was selected. Comparison of the sequence of the KmABF1 gene wit h that encoding Saccharomyces cerevisiae ABF1 and the previously isola ted ABF1-gene from Kluyveromyces lactis (KlABF1) revealed distinct reg ions displaying considerable homology and therefore most likely repres enting sequences encoding essential domains. In addition to the domain s putatively involved in DNA binding of the protein factor, two short conserved amino acid sequence elements at the C-termini of the homolog ous proteins were identified, which are proposed to play a part in the ir trans-acting functions. This is the first report on the structure o f a regulatory protein factor from K. marxianus.