Oligodeoxynucleotides Having a Loop Consisting of 3'-Deoxy-4'-C-(2-hydroxyethyl)thymidines Form Stable Hairpins
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- 作者：Yuji Yamamoto ; Satoshi Shuto ; Yutaka Tamura ; Tetsuya Kodama ; Shuichi Hoshika ; Satoshi Ichikawa ; Yoshihito Ueno ; Eiko Ohtsuka ; Yasuo Komatsu ; and Akira Matsuda
- 刊名：Biochemistry
- 出版年：2004
- 出版时间：July 13, 2004
- 年：2004
- 卷：43
- 期：27
- 页码：8690 - 8699
- 全文大小：279K
- 年卷期：v.43,no.27(July 13, 2004)
- ISSN：1520-4995
文摘
Components that form stable hairpin loops are highly useful for the development of functionalDNA and RNA molecules. We have designed and synthesized a sugar-modified thymidine analogue,3'-deoxy-4'-C-(2-hydroxyethyl)thymidine (X), as a nucleosidic loop component stabilizing the hairpinstructure. The ODNs I-1-4, 5'-d[CGAACG-Xn-CGTTCG]-3' (I-1, n = 1; I-2, n = 2; I-3, n = 3; I-4, n= 4), forming the hairpin loop structures, of which the loop moiety consisted of the analogue X, and alsothe corresponding unmodified ODNs II-1-4, 5'-d[CGAACG-Tn-CGTTCG]-3' (II-1, n = 1; II-2, n = 2;II-3, n = 3; II-4, n = 4), having a thymidine loop, were synthesized by the phosphoramidite method. Themelting temperatures (Tm) of the ODNs I-1-4 containing X in the loop moiety at 5 
M were 67.1, 68.1,73.0, and 69.3 
C, respectively, and those of the control natural ODNs II-1-4 were 65.3, 67.0, 69.2, and68.8 C, respectively. Thus, the ODNs I-1-4 formed a more thermally stable hairpin than the correspondingunmodified ODNs II-1-4 having an equal number of loop residues. The hairpin structures of the modifiedODNs I-1-4 and the unmodified ODNs II-1-4 were investigated by CD spectroscopy and molecularmechanics calculations. These results showed that the 4'-branched nucleoside X can stabilize hairpinstructures when it is present in the loop moiety, probably due to the flexibility of the one-carbon-elongated4'-branched structure.
M were 67.1, 68.1,73.0, and 69.3 C, respectively, and those of the control natural ODNs II-1-4 were 65.3, 67.0, 69.2, and68.8 C, respectively. Thus, the ODNs I-1-4 formed a more thermally stable hairpin than the correspondingunmodified ODNs II-1-4 having an equal number of loop residues. The hairpin structures of the modifiedODNs I-1-4 and the unmodified ODNs II-1-4 were investigated by CD spectroscopy and molecularmechanics calculations. These results showed that the 4'-branched nucleoside X can stabilize hairpinstructures when it is present in the loop moiety, probably due to the flexibility of the one-carbon-elongated4'-branched structure.