Hysteresis in poly‐2′‐deoxycytidine i‐motif folding is impacted by the method of analysis as well as loop and stem lengths
Hysteresis in poly‐2′‐deoxycytidine i‐motif folding is impacted by the method of analysis as well as loop and stem lengths
复制标题
聚-2-2-脱氧胞苷基序折叠的滞后受到分析方法以及环和茎长度的影响
DOI：
10.1002/bip.23389
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发表时间：
2020
期刊：
影响因子：
2.9
通讯作者：
Burrows, Cynthia J.
中科院分区：
文献类型：
--
作者：
Rogers, R. Aaron;Meyer, Madeline R.;Stewart, Kayla M.;Eyring, Gabriela M.;Fleming, Aaron M.;Burrows, Cynthia J.
在DNA中，当富含2‘-脱氧胞苷(DC)核苷酸的序列采用连续的DC自碱基对时，I-基序(Im)折叠发生在弱酸性条件下。Im的pH稳定性是由折叠和未折叠状态之间的pH转变(PHT)的中点来定义的。在长度为15、19或23个核苷酸的多DC IMS上进行了两个不同的实验，以通过圆二色谱(CD)测定pHT值。这些实验证明了两点：(1)pHT值取决于所进行的滴定实验，以及(2)pH诱导的变性或退火过程在pHT值中产生等温滞后。这些结果与具有DC到胸腺嘧啶核苷的明智突变以有利于特定折叠的模型IMS相结合，发现滞后对于较短的PolyDC IMS和具有偶数碱基对的IMS最大，而对于较长的PolyDC IMS和具有奇数碱基对的IMS最小。通过热变化跟踪Im折叠的实验发现，变性循环和退火循环之间存在热滞。与CD实验中观察到的趋势相似。结果表明，Im分析方法会对测量的pHT值产生影响，pHT值和Tm值存在滞后现象。
In DNA, i‐motif (iM) folds occur under slightly acidic conditions when sequences rich in 2′‐deoxycytidine (dC) nucleotides adopt consecutive dC self base pairs. The pH stability of an iM is defined by the midpoint in the pH transition (pHT) between the folded and unfolded states. Two different experiments to determine pHTvalues via circular dichroism (CD) spectroscopy were performed on poly‐dC iMs of length 15, 19, or 23 nucleotides. These experiments demonstrate two points: (1) pHTvalues were dependent on the titration experiment performed, and (2) pH‐induced denaturing or annealing processes produced isothermal hysteresis in the pHTvalues. These results in tandem with model iMs with judicious mutations of dC to thymidine to favor particular folds found the hysteresis was maximal for the shorter poly‐dC iMs and those with an even number of base pairs, while the hysteresis was minimal for longer poly‐dC iMs and those with an odd number of base pairs. Experiments to follow the iM folding via thermal changes identified thermal hysteresis between the denaturing and annealing cycles. Similar trends were found to those observed in the CD experiments. The results demonstrate that the method of iM analysis can impact the pHTparameter measured, and hysteresis was observed in the pHTandTmvalues.
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影响因子：
15
作者：
Kendrick, Samantha;Akiyama, Yoshitsugu;Hecht, Sidney M.;Hurley, Laurence H.
通讯作者：
Hurley, Laurence H.
影响因子：
15
作者：
Fleming, Aaron M.;Ding, Yun;Burrows, Cynthia J.
通讯作者：
Burrows, Cynthia J.
影响因子：
4.6
作者：
Cristofari, Camilla;Rigo, Riccardo;Sissi, Claudia
通讯作者：
Sissi, Claudia
影响因子：
3.2
作者：
Lieblein, Anna Lena;Fuertig, Boris;Schwalbe, Harald
通讯作者：
Schwalbe, Harald
影响因子：
14.9
作者：
Mergny, JL;Lacroix, L
通讯作者：
Lacroix, L