Structural dynamics of the glycine-binding domain of the N-methyl-D-aspartate receptor.

Autor:	Dolino DM; From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology, Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, Texas 77030 and., Cooper D; the Departments of Chemistry and., Ramaswamy S; From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology, Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, Texas 77030 and., Jaurich H; the Departments of Chemistry and., Landes CF; the Departments of Chemistry and Electrical and Computer Engineering, Rice University, Houston, Texas 77251 cflandes@rice.edu., Jayaraman V; From the Center for Membrane Biology, Department of Biochemistry and Molecular Biology, Graduate School of Biomedical Sciences, University of Texas Health Science Center, Houston, Texas 77030 and vasanthi.jayaraman@uth.tmc.edu.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2015 Jan 09; Vol. 290 (2), pp. 797-804. Date of Electronic Publication: 2014 Nov 17.
DOI:	10.1074/jbc.M114.605436
Abstrakt:	N-Methyl-D-aspartate receptors mediate the slow component of excitatory neurotransmission in the central nervous system. These receptors are obligate heteromers containing glycine- and glutamate-binding subunits. The ligands bind to a bilobed agonist-binding domain of the receptor. Previous x-ray structures of the glycine-binding domain of NMDA receptors showed no significant changes between the partial and full agonist-bound structures. Here we have used single molecule fluorescence resonance energy transfer (smFRET) to investigate the cleft closure conformational states that the glycine-binding domain of the receptor adopts in the presence of the antagonist 5,7-dichlorokynurenic acid (DCKA), the partial agonists 1-amino-1-cyclobutanecarboxylic acid (ACBC) and L-alanine, and full agonists glycine and D-serine. For these studies, we have incorporated the unnatural amino acid p-acetyl-L-phenylalanine for specific labeling of the protein with hydrazide derivatives of fluorophores. The single molecule fluorescence resonance energy transfer data show that the agonist-binding domain can adopt a wide range of cleft closure states with significant overlap in the states occupied by ligands of varying efficacy. The difference lies in the fraction of the protein in a more closed-cleft form, with full agonists having a larger fraction in the closed-cleft form, suggesting that the ability of ligands to select for these states could dictate the extent of activation. (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)
Databáze:	MEDLINE
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