Kinetics of transient end-to-end contact of single-stranded DNAs
Kinetics of transient end-to-end contact of single-stranded DNAs
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DOI：
10.1021/ja0524999
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发表时间：
2005-09-28
影响因子：
15
通讯作者：
Majima, T
中科院分区：
文献类型：
--
作者：
Kawai, K;Yoshida, H;Majima, T
利用芘（Py）二聚体自由基阳离子（PY2中心点+）的形成来测量单链dna （ssdna）链内端到端接触速率在10纳秒到几十微秒的时间范围内的动力学。合成了长度分别为3、6和9 mer的两端带Py标记的ssdna，并采用双光子电离法生成了一个Py中心点+，可以测量端到端接触速率从10 ns开始。PY2中心点+的形成速率取决于ssDNA的长度和序列，富t的ssDNA的形成速率比相应长度富a的ssDNA的形成速率快1个数量级，表明由腺嘌呤组成的ssDNA比由胸腺嘧啶组成的ssDNA刚性得多。对于富t的ssdna，也观察到由于错误折叠结构而形成PY2中心dot+，这与Ansari等提出的构型扩散模型一致。
The formation of the pyrene (Py) dimer radical cation (PY2 center dot+) was used to measure the kinetics of the intrastrand end-to-end contact rates of single-stranded DNAs (ssDNAs) in the 10 nanoseconds to the tens of microseconds time range. ssDNAs labeled with Py at both ends with the lengths of 3, 6, and 9 mer were synthesized, and the two-photon ionization method was employed to generate a Py center dot+, which enables the measurements of the end-to-end contact rates from 10 ns. The formation rate of PY2 center dot+ depended on the length and the sequence of the ssDNAs, and about 1 order of magnitude faster rates were observed for the T-rich ssDNAs compared to those for the corresponding length of A-rich ssDNAs, showing that ssDNA made from adenines is much more rigid than thatcomposed of thymidines. As forthe T-rich ssDNAs, the formation Of PY2 center dot+ attributed to the misfolded structures was also observed, which is consistent with the configurational diffusion model suggested by Ansari and co-workers.