Molecular determinants of allosteric modulation at the M1 muscarinic acetylcholine receptor

Alaa Abdul Ridha, Laura Lopez, Peter Keov, David Thal, Shailesh Natvarbhai Mistry, Patrick Sexton, Jonathan Robert David Lane, Meritxell Canals, Arthur Christopoulos

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Benzylquinolone carboxylic acid (BQCA) is an unprecedented example of a selective positive allosteric modulator of acetylcholine at the M1 muscarinic acetylcholine receptor (mAChR). To probe the structural basis underlying its selectivity, we utilized site-directed mutagenesis, analytical modeling, and molecular dynamics to delineate regions of the M1 mAChR that govern modulator binding and transmission of cooperativity. We identified Tyr-852.64 in transmembrane domain 2 (TMII), Tyr-179 and Phe-182 in the second extracellular loop (ECL2), and Glu-3977.32 and Trp-4007.35 in TMVII as residues that contribute to the BQCA binding pocket at the M1 mAChR, as well as to the transmission of cooperativity with the orthosteric agonist carbachol. As such, the BQCA binding pocket partially overlaps with the previously described common allosteric site in the extracellular vestibule of the M1 mAChR, suggesting that its high subtype selectivity derives from either additional contacts outside this region or through a subtype-specific cooperativity mechanism. Mutation of amino acid residues that form the orthosteric binding pocket caused a loss of carbachol response that could be rescued by BQCA. Two of these residues (Leu-1023.29 and Asp-1053.32) were also identified as indirect contributors to the binding affinity of the modulator. This new insight into the structural basis of binding and function of BQCA can guide the design of new allosteric ligands with tailored pharmacological properties.
Original languageEnglish
Pages (from-to)6067 - 6079
Number of pages13
JournalJournal of Biological Chemistry
Volume289
Issue number9
DOIs
Publication statusPublished - 2014

Cite this

Abdul Ridha, Alaa ; Lopez, Laura ; Keov, Peter ; Thal, David ; Mistry, Shailesh Natvarbhai ; Sexton, Patrick ; Lane, Jonathan Robert David ; Canals, Meritxell ; Christopoulos, Arthur. / Molecular determinants of allosteric modulation at the M1 muscarinic acetylcholine receptor. In: Journal of Biological Chemistry. 2014 ; Vol. 289, No. 9. pp. 6067 - 6079.
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abstract = "Benzylquinolone carboxylic acid (BQCA) is an unprecedented example of a selective positive allosteric modulator of acetylcholine at the M1 muscarinic acetylcholine receptor (mAChR). To probe the structural basis underlying its selectivity, we utilized site-directed mutagenesis, analytical modeling, and molecular dynamics to delineate regions of the M1 mAChR that govern modulator binding and transmission of cooperativity. We identified Tyr-852.64 in transmembrane domain 2 (TMII), Tyr-179 and Phe-182 in the second extracellular loop (ECL2), and Glu-3977.32 and Trp-4007.35 in TMVII as residues that contribute to the BQCA binding pocket at the M1 mAChR, as well as to the transmission of cooperativity with the orthosteric agonist carbachol. As such, the BQCA binding pocket partially overlaps with the previously described common allosteric site in the extracellular vestibule of the M1 mAChR, suggesting that its high subtype selectivity derives from either additional contacts outside this region or through a subtype-specific cooperativity mechanism. Mutation of amino acid residues that form the orthosteric binding pocket caused a loss of carbachol response that could be rescued by BQCA. Two of these residues (Leu-1023.29 and Asp-1053.32) were also identified as indirect contributors to the binding affinity of the modulator. This new insight into the structural basis of binding and function of BQCA can guide the design of new allosteric ligands with tailored pharmacological properties.",
author = "{Abdul Ridha}, Alaa and Laura Lopez and Peter Keov and David Thal and Mistry, {Shailesh Natvarbhai} and Patrick Sexton and Lane, {Jonathan Robert David} and Meritxell Canals and Arthur Christopoulos",
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Molecular determinants of allosteric modulation at the M1 muscarinic acetylcholine receptor. / Abdul Ridha, Alaa; Lopez, Laura; Keov, Peter; Thal, David; Mistry, Shailesh Natvarbhai; Sexton, Patrick; Lane, Jonathan Robert David; Canals, Meritxell; Christopoulos, Arthur.

In: Journal of Biological Chemistry, Vol. 289, No. 9, 2014, p. 6067 - 6079.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - Molecular determinants of allosteric modulation at the M1 muscarinic acetylcholine receptor

AU - Abdul Ridha, Alaa

AU - Lopez, Laura

AU - Keov, Peter

AU - Thal, David

AU - Mistry, Shailesh Natvarbhai

AU - Sexton, Patrick

AU - Lane, Jonathan Robert David

AU - Canals, Meritxell

AU - Christopoulos, Arthur

PY - 2014

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AB - Benzylquinolone carboxylic acid (BQCA) is an unprecedented example of a selective positive allosteric modulator of acetylcholine at the M1 muscarinic acetylcholine receptor (mAChR). To probe the structural basis underlying its selectivity, we utilized site-directed mutagenesis, analytical modeling, and molecular dynamics to delineate regions of the M1 mAChR that govern modulator binding and transmission of cooperativity. We identified Tyr-852.64 in transmembrane domain 2 (TMII), Tyr-179 and Phe-182 in the second extracellular loop (ECL2), and Glu-3977.32 and Trp-4007.35 in TMVII as residues that contribute to the BQCA binding pocket at the M1 mAChR, as well as to the transmission of cooperativity with the orthosteric agonist carbachol. As such, the BQCA binding pocket partially overlaps with the previously described common allosteric site in the extracellular vestibule of the M1 mAChR, suggesting that its high subtype selectivity derives from either additional contacts outside this region or through a subtype-specific cooperativity mechanism. Mutation of amino acid residues that form the orthosteric binding pocket caused a loss of carbachol response that could be rescued by BQCA. Two of these residues (Leu-1023.29 and Asp-1053.32) were also identified as indirect contributors to the binding affinity of the modulator. This new insight into the structural basis of binding and function of BQCA can guide the design of new allosteric ligands with tailored pharmacological properties.

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M3 - Article

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JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 1083-351X

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