TY - JOUR
T1 - Structural basis for AMPA receptor activation and ligand selectivity
T2 - Crystal structures of five agonist complexes with the GluR2 ligand-binding core
AU - Hogner, A.
AU - Kastrup, J. S.
AU - Jin, R.
AU - Liljefors, T.
AU - Mayer, M. L.
AU - Egebjerg, J.
AU - Larsen, I. K.
AU - Gouaux, E.
N1 - Funding Information:
We thank Lotte Brehm, Stine B. Vogensen, Ulf Madsen, and Povl Krogsgaard-Larsen for generously supplying us with (S)-2-Me-Tet-AMPA, (S)-ACPA, and (S)-Br-HIBO. We are grateful to Neali Armstrong and Rich Olson for advice and helpful assistance. Jeremy R. Greenwood is thanked for discussion and guidance using computational techniques. Victor S. Lamzin is thanked for assistance with the program ARP/wARP and Willy R. Wriggers with the HINGEFIND script. The work was supported by grants from NeuroScience PharmaBiotec; DANSYNC (Danish Centre for Synchrotron Based Research); European Community—access to Research Infrastructure Action of the Improving Human Potential Programme to the EMBL Hamburg Outstation, contract number: HPRI-CT-1999-00017; Novo Nordisk Fonden; Apotekerfonden af 1991; and the Danish Medical Research Council. Work in the Gouaux laboratory on glutamate receptors is supported by grants from NIH and NARSAD. E. Gouaux is a Klingenstein Fellow and an assistant investigator of the Howard Hughes Medical Institute.
PY - 2002
Y1 - 2002
N2 - Glutamate is the principal excitatory neurotransmitter within the mammalian CNS, playing an important role in many different functions in the brain such as learning and memory. In this study, a combination of molecular biology, X-ray structure determinations, as well as electrophysiology and binding experiments, has been used to increase our knowledge concerning the ionotropic glutamate receptor GluR2 at the molecular level. Five high-resolution X-ray structures of the ligand-binding domain of GluR2 (S1S2J) complexed with the three agonists (S)-2-amino-3-[3-hydroxy-5-(2-methyl-2H-tetrazol-5-yl)isoxazol-4-yl]propionic acid (2-Me-Tet-AMPA), (S)-2-amino-3-(3-carboxy-5-methylisoxazol-4-yl)propionic acid (ACPA), and (S)-2-amino-3-(4-bromo-3-hydroxy-isoxazol-5-yl)propionic acid (Br-HIBO), as well as of a mutant thereof (S1S2J-Y702F) in complex with ACPA and Br-HIBO, have been determined. The structures reveal that AMPA agonists with an isoxazole moiety adopt different binding modes in the receptor, dependent on the substituents of the isoxazole. Br-HIBO displays selectivity among different AMPA receptor subunits, and the design and structure determination of the S1S2J-Y702F mutant in complex with Br-HIBO and ACPA have allowed us to explain the molecular mechanism behind this selectivity and to identify key residues for ligand recognition. The agonists induce the same degree of domain closure as AMPA, except for Br-HIBO, which shows a slightly lower degree of domain closure. An excellent correlation between domain closure and efficacy has been obtained from electrophysiology experiments undertaken on non-desensitising GluR2i(Q)-L483Y receptors expressed in oocytes, providing strong evidence that receptor activation occurs as a result of domain closure. The structural results, combined with the functional studies on the full-length receptor, form a powerful platform for the design of new selective agonists.
AB - Glutamate is the principal excitatory neurotransmitter within the mammalian CNS, playing an important role in many different functions in the brain such as learning and memory. In this study, a combination of molecular biology, X-ray structure determinations, as well as electrophysiology and binding experiments, has been used to increase our knowledge concerning the ionotropic glutamate receptor GluR2 at the molecular level. Five high-resolution X-ray structures of the ligand-binding domain of GluR2 (S1S2J) complexed with the three agonists (S)-2-amino-3-[3-hydroxy-5-(2-methyl-2H-tetrazol-5-yl)isoxazol-4-yl]propionic acid (2-Me-Tet-AMPA), (S)-2-amino-3-(3-carboxy-5-methylisoxazol-4-yl)propionic acid (ACPA), and (S)-2-amino-3-(4-bromo-3-hydroxy-isoxazol-5-yl)propionic acid (Br-HIBO), as well as of a mutant thereof (S1S2J-Y702F) in complex with ACPA and Br-HIBO, have been determined. The structures reveal that AMPA agonists with an isoxazole moiety adopt different binding modes in the receptor, dependent on the substituents of the isoxazole. Br-HIBO displays selectivity among different AMPA receptor subunits, and the design and structure determination of the S1S2J-Y702F mutant in complex with Br-HIBO and ACPA have allowed us to explain the molecular mechanism behind this selectivity and to identify key residues for ligand recognition. The agonists induce the same degree of domain closure as AMPA, except for Br-HIBO, which shows a slightly lower degree of domain closure. An excellent correlation between domain closure and efficacy has been obtained from electrophysiology experiments undertaken on non-desensitising GluR2i(Q)-L483Y receptors expressed in oocytes, providing strong evidence that receptor activation occurs as a result of domain closure. The structural results, combined with the functional studies on the full-length receptor, form a powerful platform for the design of new selective agonists.
KW - Electrophysiology
KW - Glutamate receptors
KW - Ligand binding
KW - Selectivity
KW - X-ray structures
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U2 - 10.1016/S0022-2836(02)00650-2
DO - 10.1016/S0022-2836(02)00650-2
M3 - Article
C2 - 12215417
AN - SCOPUS:0036968894
SN - 0022-2836
VL - 322
SP - 93
EP - 109
JO - Journal of molecular biology
JF - Journal of molecular biology
IS - 1
ER -