Battersby Thomas R, Albalos Maria, Friesenhahn Michel J
Bayer HealthCare LLC, Diagnostics Division, Berkeley, CA 94710, USA.
Chem Biol. 2007 May;14(5):525-31. doi: 10.1016/j.chembiol.2007.03.012.
Nucleic acid duplexes associating through purine-purine base pairing have been constructed and characterized in a remarkable demonstration of nucleic acids with mixed sequence and a natural backbone in an alternative duplex structure. The antiparallel deoxyribose all-purine duplexes associate specifically through Watson-Crick pairing, violating the nucleobase size-complementarity pairing convention found in Nature. Sequence-specific recognition displayed by these structures makes the duplexes suitable, in principle, for information storage and replication fundamental to molecular evolution in all living organisms. All-purine duplexes can be formed through association of purines found in natural ribonucleosides. Key to the formation of these duplexes is the N(3)-H tautomer of isoguanine, preferred in the duplex, but not in aqueous solution. The duplexes have relevance to evolution of the modern genetic code and can be used for molecular recognition of natural nucleic acids.
通过嘌呤-嘌呤碱基配对形成的核酸双链体已被构建并表征，这是对具有混合序列和天然主链的核酸以替代双链结构的一项显著展示。反平行脱氧核糖全嘌呤双链体通过沃森-克里克配对特异性结合，违背了自然界中发现的核碱基大小互补配对规则。这些结构所显示的序列特异性识别使得双链体原则上适用于所有生物体分子进化所必需的信息存储和复制。全嘌呤双链体可通过天然核糖核苷中嘌呤的结合形成。这些双链体形成的关键是异鸟嘌呤的N(3)-H互变异构体，其在双链体中占优，但在水溶液中并非如此。这些双链体与现代遗传密码的进化相关，可用于天然核酸的分子识别。
