作者:Achim H. Krotz、Sine Larsen、Ole Buchardt、Magdalena Eriksson、Peter E. Nielsen
DOI:10.1016/s0968-0896(98)00152-7
日期:1998.11
'Retro-inverso' peptide nucleic acid (PNA) monomers of thymine (T*: N-(amidomethyl)-N-(N-1-thyminyl-acetyl)-beta-alanyl) land adenine) have been prepared and introduced in PNA oligomers. A homo 'retro-inverso' T-8* PNA was found not to hybridize to a complementary DNA or RNA oligonucleotide, whereas introduction of one retro- inverso thymine unit into the middle of a normal PNA 15-mer resulted in a ca. 8 degrees C destabilization of the complex of this oligomer with a complementary DNA or RNA oligomer. In an effort to compensate for the structural nucleobase 'phase-shift' caused by the T* monomer by also introducing a beta-alanine monomer it is concluded that the effect of the T* backbone is -7 degrees C when hybridizing to DNA and -4.5 degrees C when hybridizing to RNA. Nonetheless, the T* unit shows good sequence discrimination comparable to that of normal PNA. Molecular dynamics simulations indicate an unfavourable conformation of the backbone amide carbonyl group resulting in reduced interaction with the aqueous medium and an 'electrostatic clash' with the carbonyl of the nucleobase linker. These results show that a simple inversion of an amide bond in the PNA. backbone has a dramatic, and hardly predictable, effect on the DNA mimicking properties of the oligomer. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
'逆向-转位'胸腺嘧啶(T*: N-(酰胺甲基)-N-(1-胸腺嘧啶-乙酰基)-β-丙氨酰)和腺嘌呤肽核酸(PNA)单体已被制备并引入到PNA寡聚体中。发现一种同源的逆向-转位T-8* PNA并不与互补的DNA或RNA寡聚体杂交,而将一个逆向-转位胸腺嘧啶单位引入到正常PNA 15聚中的中间位置,导致其与互补的DNA或RNA寡聚体形成的复合物稳定性降低了约8°C。为了补偿由T*单体引起的结构碱基的"相位变化",同时引入了一个β-丙氨酸单体,结果表明,当与DNA杂交时,T*骨架的效果为-7°C,而当与RNA杂交时为-4.5°C。尽管如此,T*单位显示出与正常PNA相当的良好序列鉴别能力。分子动力学模拟表明,骨架酰胺羰基的构象不利,导致与水介质的相互作用减少,并与碱基连接物的羰基发生"静电碰撞"。这些结果表明,简单地反转PNA主链中的一个酰胺键,对寡聚体的DNA模拟性质产生了巨大且难以预测的影响。©1998 Elsevier Science Ltd.版权所有。