{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,7,7]],"date-time":"2025-07-07T05:45:02Z","timestamp":1751867102755,"version":"3.40.4"},"reference-count":6,"publisher":"S. Karger AG","issue":"2","license":[{"start":{"date-parts":[[2000,1,1]],"date-time":"2000-01-01T00:00:00Z","timestamp":946684800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"},{"start":{"date-parts":[[2000,1,1]],"date-time":"2000-01-01T00:00:00Z","timestamp":946684800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Pharmacology"],"published-print":{"date-parts":[[2000]]},"abstract":"<jats:p>The structural basis for the selectivity of the antagonist UH-AH 37 at human muscarinic acetylcholine receptors was investigated by expressing mutant receptors in COS-7 cells. Previous studies have demonstrated that the interaction between UH-AH 37 and [&lt;sup&gt;3&lt;\/sup&gt;H]N-methylscopolamine in equilibrium assays is competitive and that the high affinity of UH-AH 37 for the M&lt;sub&gt;5&lt;\/sub&gt; subtype, compared to M&lt;sub&gt;2&lt;\/sub&gt;, is due to an epitope in the sixth transmembrane domain (TM6) or the third outer loop of the receptor. By mutating each nonconserved residue in this region of M&lt;sub&gt;2&lt;\/sub&gt; and M&lt;sub&gt;5&lt;\/sub&gt; to its counterpart in the other receptor, we identified a threonine residue in the middle of TM6 uniquely responsible for the higher affinity of the M&lt;sub&gt;5&lt;\/sub&gt; receptor (M&lt;sub&gt;1&lt;\/sub&gt;, M&lt;sub&gt;3&lt;\/sub&gt;, and M&lt;sub&gt;4&lt;\/sub&gt; receptors also carry a threonine at that location and also have high affinity for UH-AH 37). The mutant receptor in which the corresponding alanine of the M&lt;sub&gt;2&lt;\/sub&gt; receptor was replaced by threonine, M&lt;sub&gt;2&lt;\/sub&gt;&lt;sup&gt;401&lt;\/sup&gt;ala \u21d2 thr, expressed enhanced affinity for pirenzepine as well as for UH-AH 37. The chick M&lt;sub&gt;2&lt;\/sub&gt; receptor, which expresses anomalously high affinity for pirenzepine, differs from its mammalian counterparts by the presence of a threonine at this position. Affinities of AF-DX 116 and 4-DAMP, as well as the allosteric potency of UH-AH 37, were not sensitive to the M&lt;sub&gt;2&lt;\/sub&gt;&lt;sup&gt;401&lt;\/sup&gt; ala \u21d2 thr mutation.<\/jats:p>","DOI":"10.1159\/000028382","type":"journal-article","created":{"date-parts":[[2003,4,15]],"date-time":"2003-04-15T13:07:10Z","timestamp":1050412030000},"page":"62-69","source":"Crossref","is-referenced-by-count":10,"title":["Site-Directed Mutagenesis Implicates a Threonine Residue in TM6 in the Subtype Selectivities of UH-AH 37 and Pirenzepine at Muscarinic Receptors"],"prefix":"10.1159","volume":"61","author":[{"given":"John","family":"Ellis","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Margaret","family":"Seidenberg","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2000,8,14]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1016\/0014-2999(95)00563-3"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.biochem.63.1.101"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.pharmtox.30.1.633"},{"key":"ref4","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1098-2299(199702)40:2<193::AID-DDR9>3.3.CO;2-8"},{"key":"ref5","doi-asserted-by":"publisher","DOI":"10.1016\/0024-3205(93)90295-E"},{"key":"ref6","doi-asserted-by":"publisher","DOI":"10.1016\/0014-5793(88)81043-3"}],"container-title":["Pharmacology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/28382","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/28382","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T04:15:55Z","timestamp":1745468155000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000028382"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000]]},"references-count":6,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2000,8,1]]}},"URL":"https:\/\/doi.org\/10.1159\/000028382","archive":["Portico"],"relation":{},"ISSN":["0031-7012","1423-0313"],"issn-type":[{"type":"print","value":"0031-7012"},{"type":"electronic","value":"1423-0313"}],"subject":[],"published":{"date-parts":[[2000]]}}}