Hypoxanthine is an unnatural base that can potentially pair with all natural nucleobases. While hypoxanthine in DNA exhibits marginal preference for pairing with cytosine (C), little is known about its pairing behavior in other DNA analogues. In this study, we synthesized a hypoxanthine-containing monomer and incorporated it into pyrrolidinyl peptide nucleic acid with α/β-peptide backbone derived from D-prolyl-(1S,2S)-2-aminocyclopentanecarboxylic acid (acpcPNA). DNA binding studies clearly revealed that hypoxanthine in acpcPNA behaves like G-analogue because it can specifically form a stable base pair with dC in DNA. The ability to replace G by hypoxanthine without affecting the base pairing properties of acpcPNA can solve a number of problems associated with G-rich acpcPNA including difficult synthesis, formation of secondary structures and fluorescence quenching.
次黄嘌呤是一种非天然碱基,有可能与所有天然核碱基配对。虽然 DNA 中的
次黄嘌呤表现出与
胞嘧啶(C)配对的边缘偏好,但人们对它在其他 DNA 类似物中的配对行为知之甚少。在这项研究中,我们合成了一种含
次黄嘌呤的单体,并将其加入到以 D-丙基-(1S,2S)-2-
氨基
环戊烷羧酸(acpc
PNA)为α/β肽骨架的
吡咯烷肽核酸中。DNA 结合研究清楚地表明,acpc
PNA 中的
次黄嘌呤与 G 类似,因为它能特异性地与 DNA 中的 dC 形成稳定的碱基配对。用
次黄嘌呤取代 G 而不影响 acpc
PNA 的碱基配对特性,可以解决与富含 G 的 acpc
PNA 相关的一系列问题,包括合成困难、形成二级结构和荧光淬灭等。