Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
Single-channel analysis of a point mutation of a conserved serine residue in the S2 ligand-binding domain of the NR2A NMDA receptor subunit.
Wyllie DJ
,
Johnston AR
,
Lipscombe D
,
Chen PE
.
???displayArticle.abstract???
We have examined the function of a conserved serine residue (Ser670) in the S2 ligand-binding region of the NR2A N-methyl-d-aspartate (NMDA) receptor subunit, using recombinant NR1/NR2A receptors expressed in Xenopus laevis oocytes. Mutation of Ser670 to glycine (S670G) in NR2A reduced the potency of glutamate by 124-fold. Single-channel conductance and the duration of apparent open periods of NR2A(S670G) receptor mutants were, however, indistinguishable from wild-type NMDA receptors. NR1/NR2A(S670G) shut-time distributions were best described by a mixture of six exponential components, and the four shortest shut intervals of each distribution were considered to occur within a channel activation (burst). Bursts of single-channel openings were fitted with a mixture of four exponential components. The longest two components carried the majority of the charge transfer and had mean durations of 9.6 +/- 0.5 and 29.6 +/- 1.5 ms. The overall channel open probability during a burst was high (mean, 0.83 +/- 0.06). Consistent with a shortening of NMDA receptor-channel burst lengths was the observation of an increased deactivation rate of macroscopic currents evoked by brief applications of glutamate to outside-out membrane patches. Correlations between shut times and adjacent open times were observed in all data records. Noticeably, shorter than average openings tended to occur next to long closed periods, whereas longer than average openings tended to occur next to short closings. Our single-channel data, together with modelling using a kinetic scheme to describe channel activations, support our hypothesis that the S670G point mutation reduces the dwell time of glutamate in its binding site.
Anson,
Single-channel analysis of an NMDA receptor possessing a mutation in the region of the glutamate binding site.
2000, Pubmed,
Xenbase
Anson,
Single-channel analysis of an NMDA receptor possessing a mutation in the region of the glutamate binding site.
2000,
Pubmed
,
Xenbase
Anson,
Identification of amino acid residues of the NR2A subunit that control glutamate potency in recombinant NR1/NR2A NMDA receptors.
1998,
Pubmed
Beato,
Openings of the rat recombinant alpha 1 homomeric glycine receptor as a function of the number of agonist molecules bound.
2002,
Pubmed
Beato,
The activation mechanism of alpha1 homomeric glycine receptors.
2004,
Pubmed
Chen,
Pharmacological insights obtained from structure-function studies of ionotropic glutamate receptors.
2006,
Pubmed
Chen,
Influence of a threonine residue in the S2 ligand binding domain in determining agonist potency and deactivation rate of recombinant NR1a/NR2D NMDA receptors.
2004,
Pubmed
,
Xenbase
Chen,
Structural features of the glutamate binding site in recombinant NR1/NR2A N-methyl-D-aspartate receptors determined by site-directed mutagenesis and molecular modeling.
2005,
Pubmed
,
Xenbase
Clapham,
Substance P reduces acetylcholine-induced currents in isolated bovine chromaffin cells.
1984,
Pubmed
Colquhoun,
Fast events in single-channel currents activated by acetylcholine and its analogues at the frog muscle end-plate.
1985,
Pubmed
Colquhoun,
Binding, gating, affinity and efficacy: the interpretation of structure-activity relationships for agonists and of the effects of mutating receptors.
1998,
Pubmed
Erreger,
Glutamate receptor gating.
2004,
Pubmed
Erreger,
Subunit-specific gating controls rat NR1/NR2A and NR1/NR2B NMDA channel kinetics and synaptic signalling profiles.
2005,
Pubmed
Erreger,
Mechanism of partial agonism at NMDA receptors for a conformationally restricted glutamate analog.
2005,
Pubmed
,
Xenbase
Furukawa,
Mechanisms of activation, inhibition and specificity: crystal structures of the NMDA receptor NR1 ligand-binding core.
2003,
Pubmed
Furukawa,
Subunit arrangement and function in NMDA receptors.
2005,
Pubmed
Gibb,
Activation of N-methyl-D-aspartate receptors by L-glutamate in cells dissociated from adult rat hippocampus.
1992,
Pubmed
Gibb,
Glutamate unbinding reveals new insights into NMDA receptor activation.
2006,
Pubmed
,
Xenbase
Hansen,
Tweaking agonist efficacy at N-methyl-D-aspartate receptors by site-directed mutagenesis.
2005,
Pubmed
,
Xenbase
Hardingham,
The Yin and Yang of NMDA receptor signalling.
2003,
Pubmed
Hatton,
Properties of the human muscle nicotinic receptor, and of the slow-channel myasthenic syndrome mutant epsilonL221F, inferred from maximum likelihood fits.
2003,
Pubmed
Laube,
Molecular determinants of agonist discrimination by NMDA receptor subunits: analysis of the glutamate binding site on the NR2B subunit.
1997,
Pubmed
Laube,
Molecular determinants of ligand discrimination in the glutamate-binding pocket of the NMDA receptor.
2004,
Pubmed
Magleby,
Burst kinetics of single calcium-activated potassium channels in cultured rat muscle.
1983,
Pubmed
Mayer,
Crystal structures of the GluR5 and GluR6 ligand binding cores: molecular mechanisms underlying kainate receptor selectivity.
2005,
Pubmed
Monyer,
Developmental and regional expression in the rat brain and functional properties of four NMDA receptors.
1994,
Pubmed
Popescu,
Modal gating of NMDA receptors and the shape of their synaptic response.
2003,
Pubmed
Popescu,
Reaction mechanism determines NMDA receptor response to repetitive stimulation.
2004,
Pubmed
Schorge,
Maximum likelihood fitting of single channel NMDA activity with a mechanism composed of independent dimers of subunits.
2005,
Pubmed
,
Xenbase
Stern,
Single-channel conductances of NMDA receptors expressed from cloned cDNAs: comparison with native receptors.
1992,
Pubmed
,
Xenbase
Vicini,
Functional and pharmacological differences between recombinant N-methyl-D-aspartate receptors.
1998,
Pubmed
Williams,
Activation of N-methyl-D-aspartate receptors by glycine: role of an aspartate residue in the M3-M4 loop of the NR1 subunit.
1996,
Pubmed
Wyllie,
Single-channel activations and concentration jumps: comparison of recombinant NR1a/NR2A and NR1a/NR2D NMDA receptors.
1998,
Pubmed
,
Xenbase