title: Allelic variants of hexose transporter Hxt3p and hexokinases Hxk1p/Hxk2p in strains of Saccharomyces cerevisiae and interspecies hybrids.
abstract: The transport of sugars across the plasma membrane is a critical step in the utilization of glucose and fructose by Saccharomyces cerevisiae during must fermentations. Variations in the molecular structure of hexose transporters and kinases may affect the ability of wine yeast strains to finish sugar fermentation, even under stressful wine conditions. In this context, we sequenced and compared genes encoding the hexose transporter Hxt3p and the kinases Hxk1p/Hxk2p of Saccharomyces strains and interspecies hybrids with different industrial usages and regional backgrounds. The Hxt3p primary structure varied in a small set of amino acids, which characterized robust yeast strains used for the production of sparkling wine or to restart stuck fermentations. In addition, interspecies hybrid strains, previously isolated at the end of spontaneous fermentations, revealed a common amino acid signature. The location and potential influence of the amino acids exchanges is discussed by means of a first modelled Hxt3p structure. In comparison, hexokinase genes were more conserved in different Saccharomyces strains and hybrids. Thus, molecular variants of the hexose carrier Hxt3p, but not of kinases, correlate with different fermentation performances of yeast.
authors.affiliation: Institute of Microbiology and Wine Research, Johannes Gutenberg University Mainz, Germany.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Zuchowska
authors.affiliation: Institute of Microbiology and Wine Research, Johannes Gutenberg University Mainz, Germany.|Institute for Molecular Biophysics, Johannes Gutenberg University Mainz, Germany.
authors.forename: Elmar
authors.initials: E
authors.lastname: Jaenicke
authors.affiliation: Institute of Microbiology and Wine Research, Johannes Gutenberg University Mainz, Germany.
authors.forename: Helmut
authors.initials: H
authors.lastname: König
authors.affiliation: Institute of Microbiology and Wine Research, Johannes Gutenberg University Mainz, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Claus
mesh_terms: D000483:Alleles; D001483:Base Sequence; D002678:Chimera; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D005632:Fructose / Q000378:metabolism; D022761:Gene Transfer, Horizontal; D005947:Glucose / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative / Q000235:genetics / Q000378:metabolism; D006593:Hexokinase / Q000235:genetics* / Q000378:metabolism; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D014920:Wine / Q000382:microbiology*
chemical_list: D051246:Glucose Transport Proteins, Facilitative; C090595:HXT3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D005632:Fructose; D000431:Ethanol; C490214:HXK2 protein, S cerevisiae; D006593:Hexokinase; D005947:Glucose
keywords: Saccharomyces; glucose and fructose consumption; hexokinases; homology modelling; interspecies hybrids; must fermentation; sugar transporter