G-Quadruplexes are four-stranded nucleic acid structures typically stabilized by GGGG tetrads. These structures are intrinsically fluorescent, which expands the known scope of nucleic acid function and raises the possibility that they could eventually be used as signaling components in label-free sensors constructed from DNA or RNA. In this study, we systematically investigated the effects of mutations in tetrads, loops, and overhanging nucleotides on the fluorescence intensity and maximum emission wavelength of >500 sequence variants of a reference DNA G-quadruplex. Some of these mutations modestly increased the fluorescence intensity of this G-quadruplex, while others shifted its maximum emission wavelength. Mutations that increased the fluorescence intensity were distinct from those that increased the maximum emission wavelength, suggesting a trade-off between these two biochemical properties. The fluorescence intensity and maximum emission wavelength were also correlated with multimeric state: the most fluorescent G-quadruplexes were monomers, while those with the highest maximum emission wavelengths typically formed dimeric structures. Oligonucleotides containing multiple G-quadruplexes were in some cases more fluorescent than those containing a single G-quadruplex, although this depended on the length and sequence of the spacer linking the G-quadruplexes. These experiments provide new insights into the properties of fluorescent G-quadruplexes and should aid in the development of improved label-free nucleic acid sensors.

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本质荧光G-四链体的序列要求

G-四链体是通常由GGGG四联体稳定的四链核酸结构。这些结构本质上是荧光的，这扩大了核酸功能的已知范围，并提高了它们最终可用作由DNA或RNA构成的无标记传感器的信号成分的可能性。在这项研究中，我们系统地研究了四分体，环和突出核苷酸中的突变对参考DNA G四联体的荧光强度和> 500个序列变异体的最大发射波长的影响。这些突变中的一些适度增加了该G-四链体的荧光强度，而另一些则改变了其最大发射波长。增加荧光强度的突变与增加最大发射波长的突变不同，建议在这两个生化特性之间进行权衡。荧光强度和最大发射波长也与多聚体状态相关：最多荧光的G-四链体是单体，而具有最大最大发射波长的那些通常形成二聚体结构。在某些情况下，含有多个G-四链体的寡核苷酸比含有单个G-四链体的寡核苷酸具有更高的荧光性，尽管这取决于连接G-四链体的间隔子的长度和序列。这些实验为荧光G-四链体的性质提供了新的见识，并应有助于开发改进的无标记核酸传感器。荧光强度和最大发射波长也与多聚体状态相关：最多荧光的G-四链体是单体，而具有最大最大发射波长的那些通常形成二聚体结构。在某些情况下，含有多个G-四链体的寡核苷酸比含有单个G-四链体的寡核苷酸具有更高的荧光性，尽管这取决于连接G-四链体的间隔子的长度和序列。这些实验为荧光G-四链体的性质提供了新的见识，并应有助于开发改进的无标记核酸传感器。荧光强度和最大发射波长也与多聚体状态相关：最多荧光的G-四链体是单体，而具有最大最大发射波长的那些通常形成二聚体结构。在某些情况下，含有多个G-四链体的寡核苷酸比含有单个G-四链体的寡核苷酸具有更高的荧光性，尽管这取决于连接G-四链体的间隔子的长度和序列。这些实验为荧光G-四链体的性质提供了新的见识，并应有助于开发改进的无标记核酸传感器。在某些情况下，包含多个G-四链体的寡核苷酸比包含单个G-四链体的寡核苷酸具有更高的荧光性，尽管这取决于连接G-四链体的间隔子的长度和序列。这些实验为荧光G-四链体的性质提供了新的见识，并应有助于开发改进的无标记核酸传感器。在某些情况下，含有多个G-四链体的寡核苷酸比含有单个G-四链体的寡核苷酸具有更高的荧光性，尽管这取决于连接G-四链体的间隔子的长度和序列。这些实验为荧光G-四链体的性质提供了新的见识，并应有助于开发改进的无标记核酸传感器。