Wang Yajun, Liu Erkai, Lam Curtis H, Perrin David M
Chemistry Dept. , UBC , 2036 Main Mall , Vancouver , BC V6T1Z1 , Canada . Email:
Chem Sci. 2018 Jan 16;9(7):1813-1821. doi: 10.1039/c7sc04491g. eCollection 2018 Feb 21.
Sequence-specific cleavage of RNA targets in the absence of a divalent metal cation (M) has been a long-standing goal in bioorganic chemistry. Herein, we report the selection of novel RNA cleaving DNAzymes that are selected using 8-histaminyl-deoxyadenosine (dATP), 5-guanidinoallyl-deoxyuridine (dUTP), and 5-aminoallyl-deoxycytidine (dCTP) along with dGTP. These modified dNTPs provide key functionalities reminiscent of the active sites of ribonucleases, notably RNase A. Of several such M-free DNAymes, DNAzyme 7-38-32 cleaves a 19 nt all-RNA substrate with multiple-turnover, under simulated physiological conditions wherein only 0.5 mM Mg was present, attaining values of of 1.06 min and a of 1.37 μM corresponding to a catalytic efficiency of ∼10 M min. Therefore, Dz7-38-32 represents a promising candidate towards the development of therapeutically efficient DNAzymes.
在不存在二价金属阳离子（M）的情况下对RNA靶标进行序列特异性切割一直是生物有机化学中长期追求的目标。在此，我们报告了新型RNA切割脱氧核酶的筛选情况，这些脱氧核酶是使用8-组胺基脱氧腺苷（dATP）、5-胍基烯丙基脱氧尿苷（dUTP）、5-氨基烯丙基脱氧胞苷（dCTP）以及dGTP筛选出来的。这些修饰的脱氧核苷三磷酸提供了类似于核糖核酸酶（特别是核糖核酸酶A）活性位点的关键功能。在几种此类无M脱氧核酶中，脱氧核酶7-38-32在模拟生理条件下（其中仅存在0.5 mM镁）以多轮反应切割一个19个核苷酸的全RNA底物，其kcat值为1.06 min-1，KM值为1.37 μM，对应催化效率约为105 M-1 min-1。因此，Dz7-38-32是开发治疗高效脱氧核酶的一个有前景的候选物。
