Kodikara Sineth G, Gleeson James T, Jakli Antal, Sprunt Samuel, Balci Hamza
Department of Physics, Kent State University, Kent, Ohio 44242, United States.
Advanced Materials and Liquid Crystals Institute, Kent State University, Kent, Ohio 44242, United States.
ACS Macro Lett. 2025 Feb 18;14(2):149-154. doi: 10.1021/acsmacrolett.4c00788. Epub 2025 Jan 22.
We investigate the impact of poly adenine (poly-A) sequences on the type and stability of liquid crystalline (LC) phases formed by concentrated solutions of gapped DNA (two duplex arms bridged by a flexible single strand) using synchrotron small-angle X-ray scattering and polarizing optical microscopy. While samples with mixed sequence form layered (smectic) phases, poly-A samples demonstrate a columnar phase at lower temperatures (5-35 °C), not previously observed in GDNA samples, and a smectic-B phase of exceptional stability at higher temperatures (35-65 °C). We present a model that connects the formation of these LC phases with the unique characteristics of poly-A sequences, which manifest in various biological contexts, including DNA condensation and nucleosome formation.
我们使用同步加速器小角X射线散射和偏光光学显微镜，研究了聚腺嘌呤（poly-A）序列对由缺口DNA（由柔性单链桥接的两个双链臂）浓溶液形成的液晶（LC）相的类型和稳定性的影响。虽然具有混合序列的样品形成层状（近晶）相，但聚-A样品在较低温度（5-35°C）下呈现出柱状相，这在缺口DNA样品中以前未曾观察到，并且在较高温度（35-65°C）下呈现出具有非凡稳定性的近晶-B相。我们提出了一个模型，将这些液晶相的形成与聚-A序列的独特特征联系起来，这些特征在包括DNA凝聚和核小体形成在内的各种生物学背景中都有体现。
