Mutation of position 5 in a ten-base DNA sequence allowed us to probe its role in the photophysical and structural properties of a DNA-stabilized silver 16 nanocluster (DNA-Ag₁₆NC). A comparison of the original T5 (thymine at position 5) compound with the new modifications: X5 (abasic site), C5 (cytosine), A5 (adenine) and G5 (guanine), was made. All mutants were able to create a similar Ag₁₆NC as formed by the original T5, however diverse packing of the crystal asymmetric units in the crystalline state and minor differences in the spectroscopic properties were observed. We showed that certain nucleotides are essential for stabilizing the Ag₁₆NC, while others are not critical and can be utilized for engineering the arrangement of the asymmetric units in the crystalline state. The latter opens up the possibility to extend the primary role of the DNA as a scaffold for encapsulating the AgNC to a secondary 3D crystal engineering tool.

中文翻译：

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位置5突变作为发射NIR的DNA稳定的Ag16纳米簇的晶体工程工具

10位碱基的DNA序列中第5位的突变使我们能够探究其在DNA稳定的银16纳米簇（DNA-Ag ₁₆ NC）的光物理和结构特性中的作用。比较了具有新修饰的原始T5（5位胸腺嘧啶）化合物：X5（绝对位点），C5（胞嘧啶），A5（腺嘌呤）和G5（鸟嘌呤）。所有突变体均能够产生与原始T5相似的Ag ₁₆ NC，但是观察到晶体状态下晶体不对称单元的不同堆积和光谱性质的微小差异。我们表明某些核苷酸对于稳定Ag ₁₆必不可少NC，尽管不是关键性的，并且可以用于工程化处于结晶态的不对称单元的排列。后者为将DNA的主要作用扩展为将AgNC封装到二级3D晶体工程工具中提供了可能性。