title: GNP1, the high-affinity glutamine permease of S. cerevisiae.
abstract: Glutamine uptake in S. cerevisiae is mediated by at least three transporters: high- and low-affinity glutamine permeases and the general amino-acid permease. We have isolated the gene encoding the high-affinity glutamine permease and named it GNP1. The amino-acid sequence of GNP1, and its hydropathy profile of 12 transmembrane domains, closely resemble those of known amino-acid permeases. The Km of GNP1 for glutamine uptake was determined to be 0.59 mM. Cells lacking GNP1 exhibit reduced levels of glutamine transport, and are resistant to a toxic analog of glutamine, L-glutamic acid gamma-monohydroxamate. Unlike other amino-acid permeases, whose expression is nitrogen-source limited, GNP1 is expressed on both rich and poor nitrogen sources.
authors.affiliation: Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: X
authors.initials: X
authors.lastname: Zhu
authors.forename: J
authors.initials: J
authors.lastname: Garrett
authors.forename: J
authors.initials: J
authors.lastname: Schreve
authors.forename: T
authors.initials: T
authors.lastname: Michaeli
mesh_terms: D000595:Amino Acid Sequence; D026923:Amino Acid Transport Systems, Basic; D026921:Amino Acid Transport Systems, Neutral; D005973:Glutamine / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
chemical_list: C420623:AGP1 protein, S cerevisiae; D026923:Amino Acid Transport Systems, Basic; D026921:Amino Acid Transport Systems, Neutral; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D005973:Glutamine; C051432:glutamine permease; D009584:Nitrogen