ジャーナル: Nat Commun / 年: 2024 タイトル: Structural insights into the agonist selectivity of the adenosine A receptor. 著者: Hidetaka S Oshima / Akiko Ogawa / Fumiya K Sano / Hiroaki Akasaka / Tomoyoshi Kawakami / Aika Iwama / Hiroyuki H Okamoto / Chisae Nagiri / Fan-Yan Wei / Wataru Shihoya / Osamu Nureki / 要旨: Adenosine receptors play pivotal roles in physiological processes. Adenosine A receptor (AR), the most recently identified adenosine receptor, is expressed in various tissues, exhibiting important ...Adenosine receptors play pivotal roles in physiological processes. Adenosine A receptor (AR), the most recently identified adenosine receptor, is expressed in various tissues, exhibiting important roles in neuron, heart, and immune cells, and is often overexpressed in tumors, highlighting the therapeutic potential of AR-selective agents. Recently, we identified RNA-derived N-methyladenosine (mA) as an endogenous agonist for AR, suggesting the relationship between RNA-derived modified adenosine and AR. Despite extensive studies on the other adenosine receptors, the selectivity mechanism of AR, especially for AR-selective agonists such as mA and namodenoson, remained elusive. Here, we identify tRNA-derived N-isopentenyl adenosine (iA) as an AR-selective ligand via screening of modified nucleosides against the adenosine receptors. Like mA, iA is found in the human body and may be an endogenous AR ligand. Our cryo-EM analyses elucidate the AR-G complexes bound to adenosine, 5'-N-ethylcarboxamidoadenosine (NECA), mA, iA, and namodenoson at overall resolutions of 3.27 Å (adenosine), 2.86 Å (NECA), 3.19 Å (mA), 3.28 Å (iA), and 3.20 Å (namodenoson), suggesting the selectivity and activation mechanism of AR. We further conduct structure-guided engineering of mA-insensitive AR, which may aid future research targeting mA and AR, providing a molecular basis for future drug discovery.