title: Solid-state NMR spectroscopy reveals anomer specific transport of galactose in the milk yeast Kluyveromyces lactis.
abstract: Genetic evidence indicates that only the β-anomer of galactose is transported to Kluyveromyces lactis cells by galactose/glucose transporter Hgt1p, and that aldose-1-epimerase encoded by GAL10 is a prerequisite for growth on galactose. Minor aldose-1-epimerases other than Gal10p also exist in K. lactis. Using a mutant defective in both aldose-1-epimerases, we show by solid-state nuclear magnetic resonance spectroscopy that only β-anomer is transported in the cell and stays without or with a slow rate of conversion to α-anomer. Signals due to intracellular β-galactose appeared at two positions, both of which were shifted towards higher magnetic fields than that of β-galactose in aqueous solution, suggesting that incorporated galactose binds to cellular components, probably proteins.
authors.affiliation: Laboratory of Bacterial Infection, Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan. toshfuka@axel.ocn.ne.jp
authors.forename: Toshio
authors.initials: T
authors.lastname: Fukasawa
authors.forename: Akio
authors.initials: A
authors.lastname: Abe
authors.forename: Atsusi
authors.initials: A
authors.lastname: Nakamura
authors.forename: Miyako
authors.initials: M
authors.lastname: Horigome
authors.forename: Akira
authors.initials: A
authors.lastname: Naito
mesh_terms: D001692:Biological Transport; D002238:Carbohydrate Epimerases / Q000235:genetics; D005690:Galactose / Q000737:chemistry / Q000378:metabolism*; D017353:Gene Deletion; D007536:Isomerism; D007716:Kluyveromyces / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy
chemical_list: D002238:Carbohydrate Epimerases; C019646:aldose 1-epimerase; D005690:Galactose