Chemical Sensors based on Higher-Ordered Structures of Abiotic Nucleobases

1. 在焦磷酸盐诱导的胸腺嘧啶功能化异硫脲受体自组装中，模板辅助优先形成同步光二聚体：阴离子模板对胸腺嘧啶功能化异硫脲受体光二聚化的影响进行了研究。受体在紫外线照射下在胸腺嘧啶部分与甲醇形成光二聚体，而异硫脲部分则通过两点氢键基序作用于氧阴离子结合位点。与游离受体相比，焦磷酸盐（PPi）的存在导致顺式syn型光二聚体的优先形成，这将是识别模板化PPi的理想条件。通过氢键鸟苷八聚体荧光检测肌酐：我们报道了基于鸟苷的八聚体的设计和表征，这些八聚体由24个氢键和堆叠相互作用结合在一起，能够荧光检测临床重要的底物。八聚体由两个c…多环鸟苷四重奏组成，一个由Hoogsteen碱基配对形成，两个四重奏也由氢键耦合在一起，以逆时针旋转堆叠。当肌酸酐通过三个类似于沃森-克里克碱基配对的氢键与八聚体的鸟苷结合时，标有芘的八聚体解离成单体形式，并伴随可见荧光从绿色变为紫色。利用含有DNA链的碱基位点进行水中核碱基识别：利用碱基位点（AP位点）作为分子识别场，成功地实现了水中核碱基的识别。我们有意将AP位点构建为DNA双工，以便将AP位点定位于目标核碱基，并检测了2-氨基-7-甲基萘啶（AMND）与AP位点核碱基的络合作用。发现AMND选择性地结合胞嘧啶碱基（K_<11>>10^6M^1）并伴有显著的荧光猝灭，可用于选择性和可见地检测与胞嘧啶碱基相关的单碱基交替。少

1. Template-assisted preferential formation of syn photodimer in a pyrophosphate-induced self-assembly of a thymine-functionalized isothiouronium receptor: The effect of anion-templation is investigated for the photodimerization of a thymine-functionalized isothiouronium receptor. The receptor forms a photodimer at the thymine moiety is methanol upon the UV-irradiation, while the isothiouronium moiety works as on oxoanion binding site via o two-point hydrogen-bonding motif. As compared to the case of free receptor, the presence of pyrophosphate (PPi) resulted is the preferential formation of the cis-syn type photodimer, which would be desirable to recognize the templated PPi.Fluorescence Detection of Creatinine by a Hydrogen-Bonded Guanosine Octamer: We report the design and characterization of guanosine-based octamers held together by twenty-four hydrogen bonds and stacking interaction, capable of fluorescent detection of a clinically important substrate. The octamers consist of two c … More yclic guanosine-quartets, an formed by Hoogsteen base-pairing, and also by hydrogen bonds two quartets are coupled together so as to stack with a counterclockwise rotation. When creatinine binds to guanosine of the octamer by three hydrogen bonds similar to Watson-Crick base-pairing, the octamer labelled with pyrene dissociates to give a monomeric form accompanied by the change in visible fluorescence from green to purple.Use of A basic Site Containing DNA Strands for Nucleobase Recognition in Water: Nucleobase recognition in water is successfully achieved by the use of an abasic site (AP site) as the molecular recognition field. We intentionally constructed the AP site is DNA duplex so as to orient the AP site toward a target nucleobase, and examine the complexation of 2-amino-7-methylnaphthyridine (AMND) with nucleobases at the AP site. AMND is found to selectively bind to cytosine base (K_<11>>10^6M^1) accompanied by remarkable quenching of its fluorescence, and is available for selective and visible detection of a single-base alternation related to the cytosine base. Less