与非天然底物的酶促反应：DNA光解酶（大肠杆菌）识别并逆转DNA/PNA杂交双链体DNA链中的胸腺嘧啶[2+2]二聚体。
Enzymatic reaction with unnatural substrates: DNA photolyase (Escherichia coli) recognizes and reverses thymine [2+2] dimers in the DNA strand of a DNA/PNA hybrid duplex.
作者信息
Ramaiah D, Kan Y, Koch T, Orum H, Schuster G B
机构信息
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
出版信息
Proc Natl Acad Sci U S A. 1998 Oct 27;95(22):12902-5. doi: 10.1073/pnas.95.22.12902.
Peptide nucleic acids (PNA) are mimics with normal bases connected to a pseudopeptide chain that obey Watson-Crick rules to form stable duplexes with itself and natural nucleic acids. This has focused attention on PNA as therapeutic or diagnostic reagents. Duplexes formed with PNA mirror some but not all properties of DNA. One fascinating aspect of PNA biochemistry is their reaction with enzymes. Here we show an enzyme reaction that operates effectively on a PNA/DNA hybrid duplex. A DNA oligonucleotide containing a cis, syn-thymine [2+2] dimer forms a stable duplex with PNA. The hybrid duplex is recognized by photolyase, and irradiation of the complex leads to the repair of the thymine dimer. This finding provides insight into the enzyme mechanism and provides a means for the selective repair of thymine photodimers.
肽核酸（PNA）是一种模拟物，其正常碱基连接到一条假肽链上，该假肽链遵循沃森-克里克规则，可与自身以及天然核酸形成稳定的双链体。这使得人们将注意力集中在PNA作为治疗或诊断试剂上。与PNA形成的双链体反映了DNA的一些但并非全部特性。PNA生物化学的一个迷人之处在于它们与酶的反应。在这里，我们展示了一种在PNA/DNA杂交双链体上有效起作用的酶反应。一种含有顺式、同向胸腺嘧啶[2+2]二聚体的DNA寡核苷酸与PNA形成稳定的双链体。这种杂交双链体被光解酶识别，对该复合物进行照射会导致胸腺嘧啶二聚体的修复。这一发现为酶的作用机制提供了见解，并为胸腺嘧啶光二聚体的选择性修复提供了一种方法。
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