在DNA修复过程中,尿嘧啶DNA糖基化酶(UDG)通过氢键和π-π堆积相互作用将不需要的尿嘧啶拉入其活性位点。UDG仅与尿嘧啶紧密结合而不与尿嘧啶等衍生物紧密结合的原因仍不清楚。在这项研究中,我们合成了稳定的水溶性受体1a作为UDG活性位点的结构模拟物。化合物1a含有2,6-双(甘氨酰氨基)吡啶基团,该基团模拟UDG的氨基酸残基,该残基通过氢键网络与尿嘧啶相互作用。它也具有moiety部分作为π-π堆积相互作用元件和荧光探针,该探针模仿UDG活性位点中的芳香族基团(苯基和荧光吲哚基单元)。受体1a通过氢键和π-π堆积相互作用与尿嘧啶及其衍生物(包括胸腺嘧啶,5-甲酰基尿嘧啶,5-氟尿嘧啶和5-硝基尿嘧啶)以及一些DNA和RNA核苷(包括胸苷和尿苷)选择性结合。有趣的是,log K b关于尿嘧啶及其衍生物的N(3)H个单元的p K a值的图是线性的,负斜率(β)为-0.24±0.03。因此,N(3)H单元的p
Synthesis and crystal structures of fluorescent receptors for 9-butyladenine
作者:Bassam Lamale、William P. Henry、Lee M. Daniels、Cungen Zhang、Suzane M. Klein、Yu Lin Jiang
DOI:10.1016/j.tet.2008.10.041
日期:2009.1
Two pyrene containing fluorescent receptors, 2-(1-pyrenyl)benzoic acid (FR-1) and 8-(1-pyrenyl)-1-naphthoic acid (FR-2), have been designed and synthesized to mimic a pyrene dinucleotide for molecular recognition of 9-butyladenine (9-BuA). The X-ray crystal structures of the receptors FR-1 and FR-2 along with the binding substrate 9-BuA have been determined. FR-1 has the carboxyl group in the same plane as the phenyl group whereas the pyrenyl group is perpendicular to the phenyl group. However, both carboxyl and pyrenyl groups in FR-2 are parallel to each other but perpendicular to the naphthyl group. The binding constant for FR-2 to 9-BuA was found to be 7896 +/- 2187 M-1, which is 8.3-fold greater than that for FR-1 (953 +/- 129 M-1). The results indicate that the complex of 9-BuA with FR-2 is more stable than that with FR-1 by 1.2 kcal/mol. In addition, the molecular recognition of 9-BuA with the receptors can also be observed using fluorescence spectroscopy. (C) 2008 Elsevier Ltd. All rights reserved.