Rannversson Hafsteinn, Andersen Jacob, Bang-Andersen Benny, Strømgaard Kristian
Center for Biopharmaceuticals, Department of Drug Design and Pharmacology, University of Copenhagen , Jagtvej 162, 2100 Copenhagen Ø, Denmark.
Lundbeck Research, H. Lundbeck A/S , Ottiliavej 9, 2500 Valby, Denmark.
ACS Chem Biol. 2017 Oct 20;12(10):2558-2562. doi: 10.1021/acschembio.7b00338. Epub 2017 Sep 26.
In spite of the important role of the human serotonin transporter (hSERT) in depression treatment, the molecular details of how antidepressant drugs bind are still not completely understood, in particular those related to potential high- and low-affinity binding sites in hSERT. Here, we utilize amber codon suppression in hSERT to encode the photo-cross-linking unnatural amino acid p-azido-l-phenylalanine into the suggested high- and low-affinity binding sites. We then employ UV-induced cross-linking with azF to map the binding site of escitalopram and paroxetine, two prototypical selective serotonin reuptake inhibitors (SSRIs). We find that the two antidepressant drugs exclusively cross-link to azF incorporated at the high-affinity binding site of hSERT, while cross-linking is not observed at the low-affinity binding site. Combined with previous homology models and recent structural data on hSERT, our results provide important information to understand the molecular details of these clinical relevant binding sites.
尽管人类血清素转运体（hSERT）在抑郁症治疗中起着重要作用，但抗抑郁药物的结合分子细节仍未完全了解，特别是那些与hSERT中潜在的高亲和力和低亲和力结合位点相关的细节。在此，我们利用hSERT中的琥珀密码子抑制，将光交联非天然氨基酸对叠氮基-L-苯丙氨酸编码到建议的高亲和力和低亲和力结合位点中。然后，我们采用紫外线诱导的与叠氮苯丙氨酸（azF）的交联来绘制两种典型的选择性5-羟色胺再摄取抑制剂（SSRI）——艾司西酞普兰和帕罗西汀的结合位点。我们发现，这两种抗抑郁药物仅与hSERT高亲和力结合位点处掺入的azF发生交联，而在低亲和力结合位点未观察到交联。结合先前的同源模型和hSERT的最新结构数据，我们的结果为理解这些临床相关结合位点的分子细节提供了重要信息。
