作者:Gérald Mathis、Stéphane Bourg、Samia Aci-Sèche、Jean-Christophe Truffert、Ulysse Asseline
DOI:10.1039/c2ob26871j
日期:——
2â²-O-Neopentyldeoxyuridine (Un) was synthesized and incorporated into a series of oligodeoxyribonucleotides. Single and triple incorporations in various arrangements were performed. The Watson and Crick pairing properties with complementary DNA and RNA were investigated by UV melting curves, CD spectroscopy, and molecular dynamic simulations. The results were compared to those obtained with DNAâDNA and DNAâRNA duplexes involving dU at the same positions. Oligonucleotides containing Un clearly demonstrated their ability to form duplexes with both complementary DNA and RNA but with higher stabilities for the DNAâRNA duplexes similar to the one of the parent DNAâRNA duplex. Investigations into the thermodynamic properties of these 17-base-pair duplexes revealed ÎG values (37 °C) that are in line with the measured Tm values for both the DNAâDNA and DNAâRNA duplexes. CD spectroscopic structural investigations indicated that the conformations of the DNAâDNA and DNAâRNA duplexes involving Un are similar to those of the dTârA and dUârA containing duplexes. Only small changes in intensities and weak blue shifts were observed when three Uns were incorporated into the duplexes. The results of the molecular dynamic simulations showed, for the six duplexes involving the modified nucleoside Un, calculated curvatures similar to those of the corresponding unmodified duplexes without base-pair disruption. The neopentyl group is able to be accommodated in the minor grooves of both the DNAâDNA and RNAâDNA duplexes. However, molecular dynamic simulations indicated that the Uns adopt a C2â²-exo sugar pucker conformation close to an A-helix type without perturbing the C2â²-endo sugar pucker conformations of their 2â²-deoxynucleoside neighbours. These results confirm the potential of 2â²-O-neopentyldeoxyuridine as a nucleoside surrogate for oligonucleotide based therapeutic strategies.
2'-O-新戊基脱氧尿苷(Un)被合成并纳入一系列脱氧寡核苷酸中。进行了不同排列的单次和三次纳入。通过UV熔解曲线、圆二色光谱和分子动力学模拟研究了其与互补DNA和RNA的沃森-克里克配对特性。结果与在相同位置包含dU的DNA-DNA和DNA-RNA双链体所获得的结果进行了比较。含有Un的寡核苷酸明显表现出形成与互补DNA和RNA双链体的能力,但对DNA-RNA双链体具有更高的稳定性,类似于亲本DNA-RNA双链体的稳定性。对这些17个碱基对双链体的 thermodynamic 性质的调查揭示了与DNA-DNA和DNA-RNA双链体的测定 Tm 值一致的 ΔG 值(37 °C)。圆二色光谱结构研究表明,涉及Un的DNA-DNA和DNA-RNA双链体的构象与包含dT-rA和dU-rA的双链体相似。只在双链体中纳入三个Un时观察到强度的小变化和微弱的蓝移。分子动力学模拟的结果显示,对于涉及修饰核苷Un的六个双链体,计算的曲率与相应的未修饰双链体相似,没有碱基对断裂。新戊基团能够适应DNA-DNA和RNA-DNA双链体的小沟。然而,分子动力学模拟表明,Un采取接近A型螺旋的C2'-外糖环构象,而不干扰其2'-脱氧核苷邻位的C2'-内糖环构象。这些结果证实了2'-O-新戊基脱氧尿苷作为寡核苷酸为基础的治疗策略的核苷替代品的潜力。