Geinguenaud F, Liquier J, Brevnov M G, Petrauskene O V, Alexeev Y I, Gromova E S, Taillandier E
Laboratoire de Spectroscopie Biomoléculaire, UPRES-A CNRS 7031, UFR de Médecine, Université Paris Nord, F-93017 Bobigny Cedex, France.
Biochemistry. 2000 Oct 17;39(41):12650-8. doi: 10.1021/bi000746+.
Oligonucleotides of nonregular heteropyrimidine sequences incorporating or not incorporating purine residues 5'-d(ACTCCCTTCTCCTCTCTA), 5'-d(ACTCCCTGGTCCTCTCTA), 5'-d(TCTCTCCTGGTCCCTCC), and 5'-d(TCTCTCCTCTTCCCTCC) can form self-associated parallel-stranded (ps) structures at pH 4-5.5. The ps structures were identified by studying at neutral and acidic pH UV melting transitions, FTIR spectra, and fluorescence of pyrene-labeled oligonucleotides as well as by chemical joining of 5'-phosphorylated oligonucleotides. A gel electrophoresis run for oligonucleotides 5'-d(TCTCTCCTCTTCCCTCC) and 5'-d(ACTCCCTTCTCCTCTCTA) has shown the formation of homoduplexes at low DNA strand concentrations. Ps structures are held by C-C(+) base pairs and have N- and S-types of sugar puckering as detected by FTIR spectroscopy in the millimolar concentration range. Guanine inserts as well as thymine and purine inserts into an oligomeric cytosine sequence make the formation of the tetraplex i-motif unfavorable. MvaI restriction endonuclease, which recognizes the CCT/AGG sequence in DNA, does not cleave parallel pseudosubstrates.
含有或不含有嘌呤残基的非规则杂嘧啶序列的寡核苷酸5'-d(ACTCCCTTCTCCTCTCTA)、5'-d(ACTCCCTGGTCCTCTCTA)、5'-d(TCTCTCCTGGTCCCTCC)和5'-d(TCTCTCCTCTTCCCTCC)在pH 4 - 5.5时可形成自缔合平行链(ps)结构。通过在中性和酸性pH下研究紫外熔解转变、傅里叶变换红外光谱(FTIR)、芘标记寡核苷酸的荧光以及5'-磷酸化寡核苷酸的化学连接来鉴定ps结构。对寡核苷酸5'-d(TCTCTCCTCTTCCCTCC)和5'-d(ACTCCCTTCTCCTCTCTA)进行的凝胶电泳显示，在低DNA链浓度下形成了同源双链体。ps结构由C - C(+)碱基对维持，在毫摩尔浓度范围内通过FTIR光谱检测具有N型和S型糖环构象。鸟嘌呤插入以及胸腺嘧啶和嘌呤插入寡聚胞嘧啶序列会使四链体i - 基序的形成不利。识别DNA中CCT/AGG序列的MvaI限制性内切酶不会切割平行假底物。
