Phylogenetic Origin of the MAL and IMA α-Glucosidases of the International Genetic Line of Saccharomyces cerevisiae S288C

Abstract

Taking into account the accepted concept of the ancient whole genome duplication (WGD) in the yeast genus Saccharomyces, comparative analysis of the multiple α-glucosidases MAL and IMA of the genetic line Saccharomyces cerevisiae S288C and α-glucosidases of protoploid yeasts Kluyveromyces and Lachancea, which have not experienced genome duplication, was carried out. Only certain MAL and IMA isoforms of the latter two genera were shown to be in a close phylogenetic relationship to α-glucosidases MAL12, MAL32, and IMA1-IMA4 of S. cerevisiae S288C, while others were closer to the divergent IMA5. These results are consistent with the WGD concept, according to which the yeast Saccharomyces, Kluyveromyces, and Lachancea originated from the common protoploid ancestor and may therefore have common closely related α-glucosidases MAL and IMA. The identity of amino acid sequences of the IMA1-IMA4 isomaltoses of S. cerevisiae S288C to those of L. dasiensis, L. fantastica, L. fermentati, L. lanzarotensis, L. meyersii, L. quebecensis, and L. thermotolerans was 75−100%, while identity of the MAL maltoses of the same species was 75−99%. Importantly, the MAL and IMA α-glucosidases diverged independently in each genus, species, and even strain.