Salt dependence of the radius of gyration and flexibility of single-stranded DNA in solution probed by small-angle x-ray scattering
Salt dependence of the radius of gyration and flexibility of single-stranded DNA in solution probed by small-angle x-ray scattering
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DOI：
10.1103/physreve.86.021901
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发表时间：
2012-08-01
影响因子：
2.4
通讯作者：
Doniach, Sebastian
中科院分区：
文献类型：
--
作者：
Sim, Adelene Y. L.;Lipfert, Jan;Doniach, Sebastian
短单链核酸在生物过程中普遍存在；了解它们的物理特性可以为我们提供对核酸折叠和动力学的见解。我们使用小角度 X 射线散射来研究溶液中的 8-100 个残基同聚单链 DNA，无需外力或标记探针。 Poly-T 的结构整体随着离子强度的增加而变化，其变化方式与考虑分子灵活性的聚电解质持久长度理论一致。对于任何数量的残基，聚 A 始终比聚 T 更长，这可能是由于 A 残基比 T 残基倾向于形成更强的碱基堆积相互作用。
Short single-stranded nucleic acids are ubiquitous in biological processes; understanding their physical properties provides insights to nucleic acid folding and dynamics. We used small-angle x-ray scattering to study 8-100 residue homopolymeric single-stranded DNAs in solution, without external forces or labeling probes. Poly-T's structural ensemble changes with increasing ionic strength in a manner consistent with a polyelectrolyte persistence length theory that accounts for molecular flexibility. For any number of residues, poly-A is consistently more elongated than poly-T, likely due to the tendency of A residues to form stronger base-stacking interactions than T residues.