Source:http://linkedlifedata.com/resource/pubmed/id/12509432
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
10
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pubmed:dateCreated |
2003-3-3
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pubmed:abstractText |
A model of the rmGlu1 seven-transmembrane domain complexed with a negative allosteric modulator, 1-ethyl-2-methyl-6-oxo-4-(1,2,4,5-tetrahydro-benzo[d]azepin-3-yl)- 1,6-dihydro-pyrimidine-5-carbonitrile (EM-TBPC) was constructed. Although the mGlu receptors belong to the family 3 G-protein-coupled receptors with a low primary sequence similarity to rhodopsin-like receptors, the high resolution crystal structure of rhodopsin was successfully applied as a template in this model and used to select residues for site-directed mutagenesis. Three mutations, F801(6.51)A, Y805(6.55)A, and T815(7.39)M caused complete loss of the [(3)H]EM-TBPC binding and blocked the EM-TBPC-mediated inhibition of glutamate-evoked G-protein-coupled inwardly rectifying K(+) channel current and [Ca(2+)](i) response. The mutation W798(6.48)F increased the binding affinity of antagonist by 10-fold and also resulted in a marked decrease in the IC(50) value (4 versus 128 nm) compared with wild type. The V757(5.47)L mutation led to a dramatic reduction in binding affinity by 13-fold and a large increase in the IC(50) value (1160 versus 128 nm). Two mutations, N7474(5.51)A and N7504(5.54)A, increased the efficacy of the EM-TBPC block of the glutamate-evoked [Ca(2+)](i) response. We observed a striking conservation in the position of critical residues. The residues Val-757(5.47), Trp-798(6.48), Phe-801(6.51), Tyr-805(6.55), and Thr-815(7.39) are critical determinants of the EM-TBPC-binding pocket of the mGlu1 receptor, validating the rhodopsin crystal structure as a template for the family 3 G-protein-coupled receptors. In our model, the aromatic ring of EM-TBPC might interact with the cluster of aromatic residues formed from Trp-798(6.48), Phe-801(6.51), and Tyr-805(6.55), thereby blocking the movement of the TM6 helix, which is crucial for receptor activation.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
7
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pubmed:volume |
278
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
8340-7
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pubmed:dateRevised |
2005-11-17
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pubmed:meshHeading |
pubmed-meshheading:12509432-Allosteric Site,
pubmed-meshheading:12509432-Amino Acid Sequence,
pubmed-meshheading:12509432-Animals,
pubmed-meshheading:12509432-CHO Cells,
pubmed-meshheading:12509432-Cricetinae,
pubmed-meshheading:12509432-Humans,
pubmed-meshheading:12509432-Models, Molecular,
pubmed-meshheading:12509432-Molecular Sequence Data,
pubmed-meshheading:12509432-Mutagenesis, Site-Directed,
pubmed-meshheading:12509432-Receptors, Metabotropic Glutamate,
pubmed-meshheading:12509432-Sequence Homology, Amino Acid
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pubmed:year |
2003
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pubmed:articleTitle |
Mutational analysis and molecular modeling of the allosteric binding site of a novel, selective, noncompetitive antagonist of the metabotropic glutamate 1 receptor.
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pubmed:affiliation |
Pharma Division, Discovery Research CNS and Chemistry, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland. parichehr.malherbe@roche.com
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pubmed:publicationType |
Journal Article
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