Kierzek Elzbieta, Ciesielska Anna, Pasternak Karol, Mathews David H, Turner Douglas H, Kierzek Ryszard
Department of Chemistry, University of Rochester RC Box 270216, Rochester, NY 14627-0216, USA.
Nucleic Acids Res. 2005 Sep 9;33(16):5082-93. doi: 10.1093/nar/gki789. Print 2005.
The influence of locked nucleic acid (LNA) residues on the thermodynamic properties of 2'-O-methyl RNA/RNA heteroduplexes is reported. Optical melting studies indicate that LNA incorporated into an otherwise 2'-O-methyl RNA oligonucleotide usually, but not always, enhances the stabilities of complementary duplexes formed with RNA. Several trends are apparent, including: (i) a 3' terminal U LNA and 5' terminal LNAs are less stabilizing than interior and other 3' terminal LNAs; (ii) most of the stability enhancement is achieved when LNA nucleotides are separated by at least one 2'-O-methyl nucleotide; and (iii) the effects of LNA substitutions are approximately additive when the LNA nucleotides are separated by at least one 2'-O-methyl nucleotide. An equation is proposed to approximate the stabilities of complementary duplexes formed with RNA when at least one 2'-O-methyl nucleotide separates LNA nucleotides. The sequence dependence of 2'-O-methyl RNA/RNA duplexes appears to be similar to that of RNA/RNA duplexes, and preliminary nearest-neighbor free energy increments at 37 degrees C are presented for 2'-O-methyl RNA/RNA duplexes. Internal mismatches with LNA nucleotides significantly destabilize duplexes with RNA.
报道了锁核酸（LNA）残基对2'-O-甲基RNA/RNA异源双链体热力学性质的影响。光学熔解研究表明，掺入到其他方面为2'-O-甲基RNA寡核苷酸中的LNA通常（但并非总是）会增强与RNA形成的互补双链体的稳定性。有几个趋势很明显，包括：（i）3'末端的U LNA和5'末端的LNA比内部的和其他3'末端的LNA稳定性增强作用小；（ii）当LNA核苷酸被至少一个2'-O-甲基核苷酸隔开时，大部分稳定性增强得以实现；（iii）当LNA核苷酸被至少一个2'-O-甲基核苷酸隔开时，LNA取代的影响大致是累加的。提出了一个方程，用于估算当至少一个2'-O-甲基核苷酸隔开LNA核苷酸时与RNA形成的互补双链体的稳定性。2'-O-甲基RNA/RNA双链体的序列依赖性似乎与RNA/RNA双链体相似，并且给出了2'-O-甲基RNA/RNA双链体在37℃时的初步近邻自由能增量。与LNA核苷酸的内部错配会显著降低与RNA双链体的稳定性。
