Structure Determination of an AgI-Mediated Cytosine-Cytosine Base Pair within DNA Duplex in Solution with 1H/15N/109Ag NMR Spectroscopy

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• 作者：Dr. Takenori Dairaku ; Dr. Kyoko Furuita ; Dr. Hajime Sato ; Dr. Jakub Šebera ; Dr. Katsuyuki Nakashima ; Dr. Jiro Kondo ; Daichi Yamanaka ; Prof. Yoshinori Kondo ; Dr. Itaru Okamoto ; Prof. Akira Ono ; Dr. Vladimí ; r Sychrovský ; Dr. Chojiro Kojima and Prof. Yoshiyuki Tanaka
• 刊名：Chemistry - A European Journal
• 出版年：2016
• 出版时间：September 5, 2016
• 年：2016
• 卷：22
• 期：37
• 页码：13028-13031
• 全文大小：1322K
• ISSN：1521-3765

文摘

The structure of an Ag^I-mediated cytosine–cytosine base pair, C–Ag^I–C, was determined with NMR spectroscopy in solution. The observation of 1-bond ¹⁵N-¹⁰⁹Ag J-coupling (¹J(¹⁵N,¹⁰⁹Ag): 83 and 84 Hz) recorded within the C–Ag^I–C base pair evidenced the N3–Ag^I–N3 linkage in C–Ag^I–C. The triplet resonances of the N4 atoms in C–Ag^I–C demonstrated that each exocyclic N4 atom exists as an amino group (−NH₂), and any isomerization and/or N4–Ag^I bonding can be excluded. The 3D structure of Ag^I–DNA complex determined with NOEs was classified as a B-form conformation with a notable propeller twist of C–Ag^I–C (−18.3±3.0°). The ¹⁰⁹Ag NMR chemical shift of C-Ag^I-C was recorded for cytidine/Ag^I complex (δ(¹⁰⁹Ag): 442 ppm) to completed full NMR characterization of the metal linkage. The structural interpretation of NMR data with quantum mechanical calculations corroborated the structure of the C–Ag^I–C base pair.