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Identification and characterization of GABA, proline and quaternary ammonium compound transporters from Arabidopsis thaliana
Author(s) -
Breitkreuz Kevin E.,
Shelp Barry J.,
Fischer Wolf N.,
Schwacke Rainer,
Rentsch Doris
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)00516-5
Subject(s) - arabidopsis thaliana , transporter , proline , chemistry , biochemistry , ammonium , identification (biology) , arabidopsis , biology , botany , amino acid , gene , organic chemistry , mutant
Arabidopsis thaliana grows efficiently on GABA as the sole nitrogen source, thereby providing evidence for the existence of GABA transporters in plants. Heterologous complementation of a GABA uptake‐deficient yeast mutant identified two previously known plant amino acid transporters, AAP3 and ProT2, as GABA transporters with Michaelis constants of 12.9±1.7 and 1.7±0.3 mM at pH 4, respectively. The simultaneous transport of [1‐ 14 C]GABA and [2,3‐ 3 H]proline by ProT2 as a function of pH, provided evidence that the zwitterionic state of GABA is an important parameter in substrate recognition. ProT2‐mediated [1‐ 14 C]GABA transport was inhibited by proline and quaternary ammonium compounds.