Department of Chemistry, Yeungnam University, Dae-dong, Gyeongsan City, Republic of Korea.
College of Basic Education, Yeungnam University, Dae-dong, Gyeongsan City, Republic of Korea.
J Biomol Struct Dyn. 2020 Jun;38(9):2575-2581. doi: 10.1080/07391102.2019.1662846. Epub 2019 Sep 15.
This study examined the influence of the molecular crowding condition induced by polyethylene glycol (PEG) on the G-quadruplex structure of the thrombin-binding aptamer sequence, 5'-GGGTTGGGTGTGGGTTGGG (G3), in a solution containing a sufficient concentration of mono cations (K and Na). Although the G3 sequence preferably formed the antiparallel type G-quadruplex structure in a Na solution, conversion to the parallel type occurred when PEG was added. The antiparallel type was maintained at low PEG concentrations. When the PEG concentration reached 30%, the antiparallel type and parallel type coexist. At PEG concentrations above 40%, the G-quadruplex structure adopted the parallel type completely. In the presence of K ions, G3 showed a parallel conformation and remained as a parallel conformation with increasing PEG concentration. The dissociation temperature increased with increasing PEG concentration in all cases, suggesting that the G-quadruplex conformation is more stable under molecular crowding conditions.Communicated by Ramaswamy H. Sarma.
这项研究考察了在含有足够浓度的单价阳离子（K 和 Na）的溶液中，聚乙二醇（PEG）诱导的分子拥挤条件对凝血酶结合适体序列 5'-GGGTTGGGTGTGGGTTGGG（G3）的 G-四链体结构的影响。尽管 G3 序列在 Na 溶液中优先形成反平行型 G-四链体结构，但当添加 PEG 时会发生向平行型的转化。在低 PEG 浓度下保持反平行型。当 PEG 浓度达到 30%时，反平行型和平行型共存。当 PEG 浓度高于 40%时，G-四链体结构完全采用平行型。在 K 离子存在下，G3 表现出平行构象，并且随着 PEG 浓度的增加保持平行构象。在所有情况下，解离温度都随 PEG 浓度的增加而升高，这表明在分子拥挤条件下 G-四链体构象更稳定。由 Ramaswamy H. Sarma 交流。
