title: Cloning and characterization of the MAL11 gene encoding a high-affinity maltose transporter from Torulaspora delbrueckii.
abstract: The transport and regulation of maltose utilization by Torulaspora delbrueckii, one of the most abundant non-Saccharomyces species present in home-made corn and rye bread dough, has been investigated. A DNA fragment containing the MAL11 gene from T. delbrueckii (TdMAL11) was isolated by complementation cloning in Saccharomyces cerevisiae. DNA sequence analysis revealed the presence of an open reading frame (ORF) of 1884 bp, encoding a 627-amino acid membrane protein, which displays high homology to other yeast maltose transporters. Upstream of TdMAL11, the DNA insert contained a partial ORF (TdMAL12) on the opposite strand, which showed high similarity to the S. cerevisiae MAL12 gene. Sequence analysis, Northern blot and transport measurements indicated that TdMAL11 expression is regulated by the carbon source. Attempts to disrupt TdMAL11 revealed the presence of two functional MAL loci. Disruption of a single copy decreased the V(max) of maltose transport, but not the K(m), whereas the double disruption abolished the uptake of this sugar in T. delbrueckii.
authors.affiliation: Department of Biology, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Cecília
authors.initials: C
authors.lastname: Alves-Araújo
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Hernandez-Lopez
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Sousa
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Prieto
authors.forename: Francisca
authors.initials: F
authors.lastname: Randez-Gil
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D003001:Cloning, Molecular; D017931:DNA Primers; D007700:Kinetics; D008320:Maltose / Q000378:metabolism; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000235:genetics* / Q000378:metabolism; D016366:Open Reading Frames; D011994:Recombinant Proteins / Q000378:metabolism; D004718:Saccharomycetales / Q000235:genetics* / Q000378:metabolism
chemical_list: D017931:DNA Primers; D009004:Monosaccharide Transport Proteins; D011994:Recombinant Proteins; D008320:Maltose