Functional properties of the Arabidopsis peptide transporters AtPTR1 and AtPTR5

Ulrich Z. Hammes, Stefan Meier, Daniela Dietrich, John M. Ward, Doris Rentsch

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The Arabidopsis di- and tripeptide transporters AtPTR1 and AtPTR5 were expressed in Xenopus laevis oocytes, and their selectivity and kinetic properties were determined by voltage clamping and by radioactive uptake. Dipeptide transport by AtPTR1 and AtPTR5 was found to be electrogenic and dependent on protons but not sodium. In the absence of dipeptides, both transporters showed proton-dependent leak currents that were inhibited by Phe-Ala (AtPTR5) and Phe-Ala, Trp-Ala, and Phe-Phe (AtPTR1). Phe-Ala was shown to reduce leak currents by binding to the substrate-binding site with a high apparent affinity. Inhibition of leak currents was only observed when the aromatic amino acids were present at the N-terminal position. AtPTR1 and AtPTR5 transport activity was voltage-dependent, and currents increased supralinearly with more negative membrane potentials and did not saturate. The voltage dependence of the apparent affinities differed between Ala-Ala, Ala-Lys, and Ala-Asp and was not conserved between the two transporters. The apparent affinity of AtPTR1 for these dipeptides was pH-dependent and decreased with decreasing proton concentration. In contrast to most proton-coupled transporters characterized so far, -Imax increased at high pH, indicating that regulation of the transporter by pH overrides the importance of protons as co-substrate.

Original languageEnglish (US)
Pages (from-to)39710-39717
Number of pages8
JournalJournal of Biological Chemistry
Volume285
Issue number51
DOIs
StatePublished - Dec 17 2010

Fingerprint

phenylalanylalanine
Arabidopsis
Dipeptides
Protons
alanylaspartic acid
phenylalanylphenylalanine
Electric potential
Aromatic Amino Acids
Xenopus laevis
Substrates
Constriction
Membrane Potentials
Oocytes
Sodium
Binding Sites
peptide permease
Membranes
Kinetics

Cite this

Functional properties of the Arabidopsis peptide transporters AtPTR1 and AtPTR5. / Hammes, Ulrich Z.; Meier, Stefan; Dietrich, Daniela; Ward, John M.; Rentsch, Doris.

In: Journal of Biological Chemistry, Vol. 285, No. 51, 17.12.2010, p. 39710-39717.

Research output: Contribution to journalArticle

Hammes, Ulrich Z. ; Meier, Stefan ; Dietrich, Daniela ; Ward, John M. ; Rentsch, Doris. / Functional properties of the Arabidopsis peptide transporters AtPTR1 and AtPTR5. In: Journal of Biological Chemistry. 2010 ; Vol. 285, No. 51. pp. 39710-39717.
@article{d242b9979e6d4588896e57828b321e32,
title = "Functional properties of the Arabidopsis peptide transporters AtPTR1 and AtPTR5",
abstract = "The Arabidopsis di- and tripeptide transporters AtPTR1 and AtPTR5 were expressed in Xenopus laevis oocytes, and their selectivity and kinetic properties were determined by voltage clamping and by radioactive uptake. Dipeptide transport by AtPTR1 and AtPTR5 was found to be electrogenic and dependent on protons but not sodium. In the absence of dipeptides, both transporters showed proton-dependent leak currents that were inhibited by Phe-Ala (AtPTR5) and Phe-Ala, Trp-Ala, and Phe-Phe (AtPTR1). Phe-Ala was shown to reduce leak currents by binding to the substrate-binding site with a high apparent affinity. Inhibition of leak currents was only observed when the aromatic amino acids were present at the N-terminal position. AtPTR1 and AtPTR5 transport activity was voltage-dependent, and currents increased supralinearly with more negative membrane potentials and did not saturate. The voltage dependence of the apparent affinities differed between Ala-Ala, Ala-Lys, and Ala-Asp and was not conserved between the two transporters. The apparent affinity of AtPTR1 for these dipeptides was pH-dependent and decreased with decreasing proton concentration. In contrast to most proton-coupled transporters characterized so far, -Imax increased at high pH, indicating that regulation of the transporter by pH overrides the importance of protons as co-substrate.",
author = "Hammes, {Ulrich Z.} and Stefan Meier and Daniela Dietrich and Ward, {John M.} and Doris Rentsch",
year = "2010",
month = "12",
day = "17",
doi = "10.1074/jbc.M110.141457",
language = "English (US)",
volume = "285",
pages = "39710--39717",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "51",

}

TY - JOUR

T1 - Functional properties of the Arabidopsis peptide transporters AtPTR1 and AtPTR5

AU - Hammes, Ulrich Z.

AU - Meier, Stefan

AU - Dietrich, Daniela

AU - Ward, John M.

AU - Rentsch, Doris

PY - 2010/12/17

Y1 - 2010/12/17

N2 - The Arabidopsis di- and tripeptide transporters AtPTR1 and AtPTR5 were expressed in Xenopus laevis oocytes, and their selectivity and kinetic properties were determined by voltage clamping and by radioactive uptake. Dipeptide transport by AtPTR1 and AtPTR5 was found to be electrogenic and dependent on protons but not sodium. In the absence of dipeptides, both transporters showed proton-dependent leak currents that were inhibited by Phe-Ala (AtPTR5) and Phe-Ala, Trp-Ala, and Phe-Phe (AtPTR1). Phe-Ala was shown to reduce leak currents by binding to the substrate-binding site with a high apparent affinity. Inhibition of leak currents was only observed when the aromatic amino acids were present at the N-terminal position. AtPTR1 and AtPTR5 transport activity was voltage-dependent, and currents increased supralinearly with more negative membrane potentials and did not saturate. The voltage dependence of the apparent affinities differed between Ala-Ala, Ala-Lys, and Ala-Asp and was not conserved between the two transporters. The apparent affinity of AtPTR1 for these dipeptides was pH-dependent and decreased with decreasing proton concentration. In contrast to most proton-coupled transporters characterized so far, -Imax increased at high pH, indicating that regulation of the transporter by pH overrides the importance of protons as co-substrate.

AB - The Arabidopsis di- and tripeptide transporters AtPTR1 and AtPTR5 were expressed in Xenopus laevis oocytes, and their selectivity and kinetic properties were determined by voltage clamping and by radioactive uptake. Dipeptide transport by AtPTR1 and AtPTR5 was found to be electrogenic and dependent on protons but not sodium. In the absence of dipeptides, both transporters showed proton-dependent leak currents that were inhibited by Phe-Ala (AtPTR5) and Phe-Ala, Trp-Ala, and Phe-Phe (AtPTR1). Phe-Ala was shown to reduce leak currents by binding to the substrate-binding site with a high apparent affinity. Inhibition of leak currents was only observed when the aromatic amino acids were present at the N-terminal position. AtPTR1 and AtPTR5 transport activity was voltage-dependent, and currents increased supralinearly with more negative membrane potentials and did not saturate. The voltage dependence of the apparent affinities differed between Ala-Ala, Ala-Lys, and Ala-Asp and was not conserved between the two transporters. The apparent affinity of AtPTR1 for these dipeptides was pH-dependent and decreased with decreasing proton concentration. In contrast to most proton-coupled transporters characterized so far, -Imax increased at high pH, indicating that regulation of the transporter by pH overrides the importance of protons as co-substrate.

UR - http://www.scopus.com/inward/record.url?scp=78650065769&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=78650065769&partnerID=8YFLogxK

U2 - 10.1074/jbc.M110.141457

DO - 10.1074/jbc.M110.141457

M3 - Article

C2 - 20937801

AN - SCOPUS:78650065769

VL - 285

SP - 39710

EP - 39717

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 51

ER -