Liu Yu, Wang Risheng, Ding Liang, Sha Ruojie, Lukeman Philip S, Canary James W, Seeman Nadrian C
Department of Chemistry, New York University, 100 Washington Square E., New York, NY 10003, USA.
Chembiochem. 2008 Jul 2;9(10):1641-8. doi: 10.1002/cbic.200800032.
The stability and structure of nylon nucleic acid duplexes with complementary DNA and RNA strands was examined. Thermal denaturing studies of a series of oligonucleotides that contained nylon nucleic acids (1-5 amide linkages) revealed that the amide linkage significantly enhanced the binding affinity of nylon nucleic acids towards both complementary DNA (up to 26 degrees C increase in the thermal transition temperature (T(m)) for five linkages) and RNA (around 15 degrees C increase in T(m) for five linkages) compared with nonamide linked precursor strands. For both DNA and RNA complements, increasing derivatization decreased the melting temperatures of uncoupled molecules relative to unmodified strands; by contrast, increasing lengths of coupled copolymer raised T(m) from less to slightly greater than T(m) of unmodified strands. Thermodynamic data extracted from melting curves and CD spectra of nylon nucleic acid duplexes were consistent with loss of stability due to incorporation of pendent groups on the 2'-position of ribose and recovery of stability upon linkage of the side chains.
对具有互补DNA和RNA链的尼龙核酸双链体的稳定性和结构进行了研究。对一系列含有尼龙核酸（1 - 5个酰胺键）的寡核苷酸进行的热变性研究表明，与无酰胺键连接的前体链相比，酰胺键显著增强了尼龙核酸对互补DNA（五个键时热转变温度（T(m)）最多增加26℃）和RNA（五个键时T(m)增加约15℃）的结合亲和力。对于DNA和RNA互补链，相对于未修饰的链，增加衍生化会降低未偶联分子的解链温度；相比之下，增加偶联共聚物的长度会使T(m)从不高于未修饰链的T(m)增加到略高于未修饰链的T(m)。从尼龙核酸双链体的熔解曲线和圆二色光谱中提取的热力学数据与由于核糖2'-位上侧链基团的掺入导致稳定性丧失以及侧链连接后稳定性恢复一致。
