Chemical and bacterial reduction of azo-probes: monitoring a conformational change using fluorescence spectroscopy
作者:Nicholas J.W. Rattray、Waleed A. Zalloum、David Mansell、Joe Latimer、Mohammed Jaffar、Elena V. Bichenkova、Sally Freeman
DOI:10.1016/j.tet.2013.01.086
日期:2013.4
tetra-equatorial chair conformation, thus minimising interaction of the bisdansyl or bispyrenoyl groups. This induces a change in fluorescence from a cooperative green emission dimer band to a blue-shifted, monomer type fluorescence, with λmax 448 nm and 396 nm for the reduced forms (16) and (17), respectively. The azo-bond conformational lock can either be reduced under biomimetic conditions (using sodium dithionite)
受空间限制的探针2,4 - O-双丹酰基-6,7-二氮杂双环[3.2.1] oct-6-ene(8)和2,4 - O-双嘧啶基-6,7-二氮杂双环[3.2.1] oct- 6-烯(9)表现出特定的二聚体荧光特性(分别为λmax分别为555 nm和511 nm),这归因于丹磺酰基或groups基的2,4-双轴排列。还原(8)和(9)中的偶氮构象锁定基团,得到1,3-双丹酰基-4,6-二氨基环己烷(16)和1,3-双嘧啶基-4,6-二氨基环己烷(17))在四赤道椅构象中,因此使双丹磺酰基或双嘧啶酰基的相互作用减至最小。这导致荧光的变化从一个合作绿色发射二聚体带的蓝移,单体型荧光,与λ最大448纳米和396纳米的还原形式(16)和(17)表示。可以在仿生条件下(使用连二亚硫酸钠)或通过使用偶氮还原酶的细菌(产气荚膜梭状芽胞杆菌或大肠杆菌)降低偶氮键的构象锁定。这些荧光探针具有特异性检测表达偶氮还原酶的细菌的潜力。