| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Biophysical Journal 70: 762-777 (1996)
© 1996 the Biophysical Society
Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena 91125, USA.
ABSTRACT
Ion-coupled transporters are simulated by a model that differs from contemporary alternating-access schemes. Beginning with concepts derived from multi-ion pores, the model assumes that substrates (both inorganic ions and small organic molecules) hop a) between the solutions and binding sites and b) between binding sites within a single-file pore. No two substrates can simultaneously occupy the same site. Rate constants for hopping can be increased both a) when substrates in two sites attract each other into a vacant site between them and b) when substrates in adjacent sites repel each other. Hopping rate constants for charged substrates are also modified by the membrane field. For a three-site model, simulated annealing yields parameters to fit steady-state measurements of flux coupling, transport-associated currents, and charge movements for the GABA transporter GAT1. The model then accounts for some GAT1 kinetic data as well. The model also yields parameters that describe the available data for the rat 5-HT transporter and for the rabbit Na(+)-glucose transporter. The simulations show that coupled fluxes and other aspects of ion transport can be explained by a model that includes local substrate-substrate interactions but no explicit global conformational changes.
This article has been cited by other articles:
 |
|
 |
|
  A. Rivetta, C. Slayman, and T. Kuroda Quantitative Modeling of Chloride Conductance in Yeast TRK Potassium Transporters Biophys. J., October 1, 2005; 89(4): 2412 - 2426. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Soragna, E. Bossi, S. Giovannardi, R. Pisani, and A. Peres Relations between substrate affinities and charge equilibration rates in the rat GABA cotransporter GAT1 J. Physiol., January 15, 2005; 562(2): 333 - 345. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. D.F. Loo, B. A. Hirayama, A. Cha, F. Bezanilla, and E. M. Wright Perturbation Analysis of the Voltage-sensitive Conformational Changes of the Na+/Glucose Cotransporter J. Gen. Physiol., December 28, 2004; 125(1): 13 - 36. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Peres, S. Giovannardi, E. Bossi, and R. Fesce Electrophysiological Insights into the Mechanism of Ion-Coupled Cotransporters Physiology, April 1, 2004; 19(2): 80 - 84. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. V. Adams and L. J. DeFelice Flux Coupling in the Human Serotonin Transporter Biophys. J., December 1, 2002; 83(6): 3268 - 3282. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Kohler, I. C. Forster, G. Stange, J. Biber, and H. Murer Transport Function of the Renal Type IIa Na+/Pi Cotransporter Is Codetermined by Residues in Two Opposing Linker Regions J. Gen. Physiol., October 29, 2002; 120(5): 693 - 705. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B. R. Stevens, D. H. Feldman, Z. Liu, and W. R. Harvey Conserved tyrosine-147 plays a critical role in the ligand-gated current of the epithelial cation/amino acid transporter/channel CAATCH1 J. Exp. Biol., August 15, 2002; 205(16): 2545 - 2553. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. S. Ramsey and L. J. DeFelice Serotonin Transporter Function and Pharmacology Are Sensitive to Expression Level. EVIDENCE FOR AN ENDOGENOUS REGULATORY FACTOR J. Biol. Chem., April 19, 2002; 277(17): 14475 - 14482. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Ponce, B. Biton, J. Benavides, P. Avenet, and C. Aragon Transmembrane Domain III Plays an Important Role in Ion Binding and Permeation in the Glycine Transporter GLYT2 J. Biol. Chem., April 28, 2000; 275(18): 13856 - 13862. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. H. Buschmann, R. Vaidyanathan, W. Gassmann, and J. I. Schroeder Enhancement of Na+ Uptake Currents, Time-Dependent Inward-Rectifying K+ Channel Currents, and K+ Channel Transcripts by K+ Starvation in Wheat Root Cells Plant Physiology, April 1, 2000; 122(4): 1387 - 1398. [Abstract] [Full Text]
|
|
|
|
 |
|
 J.-G. Chen and G. Rudnick Permeation and gating residues in serotonin transporter PNAS, February 1, 2000; 97(3): 1044 - 1049. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Matskevitch, C. A. Wagner, C. Stegen, S. Broer, B. Noll, T. Risler, H. M. Kwon, J. S. Handler, S. Waldegger, A. E. Busch, et al. Functional Characterization of the Betaine/gamma -Aminobutyric Acid Transporter BGT-1 Expressed in Xenopus Oocytes J. Biol. Chem., June 11, 1999; 274(24): 16709 - 16716. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. Chrispeels, N. M. Crawford, and J. I. Schroeder Proteins for Transport of Water and Mineral Nutrients across the Membranes of Plant Cells PLANT CELL, April 1, 1999; 11(4): 661 - 676. [Full Text]
|
|
|
|
 |
|
 M. PALACIN, R. ESTEVEZ, J. BERTRAN, and A. ZORZANO Molecular Biology of Mammalian Plasma Membrane Amino Acid Transporters Physiol Rev, October 1, 1998; 78(4): 969 - 1054. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Cao, M. Li, S. Mager, and H. A. Lester Amino Acid Residues that Control pH Modulation of Transport-Associated Current in Mammalian Serotonin Transporters J. Neurosci., October 1, 1998; 18(19): 7739 - 7749. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. D. F. Loo, B. A. Hirayama, E. M. Gallardo, J. T. Lam, E. Turk, and E. M. Wright Conformational changes couple Na+ and glucose transport PNAS, June 23, 1998; 95(13): 7789 - 7794. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Galli, C.I. Petersen, M. deBlaquiere, R.D. Blakely, and L.J. DeFelice Drosophila Serotonin Transporters Have Voltage-Dependent Uptake Coupled to a Serotonin-Gated Ion Channel J. Neurosci., May 15, 1997; 17(10): 3401 - 3411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Cao, S. Mager, and H. A. Lester H+ Permeation and pH Regulation at a Mammalian Serotonin Transporter J. Neurosci., April 1, 1997; 17(7): 2257 - 2266. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Nussberger, A. Steel, D. Trotti, M. F. Romero, W. F. Boron, and M. A. Hediger Symmetry of H+ Binding to the Intra- and Extracellular Side of the H+-coupled Oligopeptide Cotransporter PepT1 J. Biol. Chem., March 21, 1997; 272(12): 7777 - 7785. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Mager, N. Kleinberger-Doron, G. I. Keshet, N. Davidson, B. I. Kanner, and H. A. Lester Ion Binding and Permeation at the GABA Transporter GAT1 J. Neurosci., September 1, 1996; 16(17): 5405 - 5414. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. H. Feldman, W. R. Harvey, and B. R. Stevens A Novel Electrogenic Amino Acid Transporter Is Activated by K+ or Na+, Is Alkaline pH-dependent, and Is Cl--independent J. Biol. Chem., August 4, 2000; 275(32): 24518 - 24526. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Kohler, I. C. Forster, G. Stange, J. Biber, and H. Murer Identification of functionally important sites in the first intracellular loop of the NaPi-IIa cotransporter Am J Physiol Renal Physiol, April 1, 2002; 282(4): F687 - F696. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
