Work Emily M, Ferraudi Guillermo, Kiefer Luke, Liu Gang, Grigalunas Michael, Bhardwaj Atul, Kaur Rasmin, Dempsey Janel M, Wüstner Daniel, Helquist Paul, Wiest Olaf
Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46566, United States.
Radiation Research Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States.
J Org Chem. 2021 Jan 15;86(2):1612-1621. doi: 10.1021/acs.joc.0c02460. Epub 2020 Dec 28.
The development of new chemical tools with improved properties is essential to chemical and cell biology. Of particular interest is the development of mimics of small molecules with important cellular function that allow the direct observation of their trafficking in a cell. To this end, a novel 15-azasterol has been designed and synthesized as a luminescent cholesterol mimic for the monitoring of cholesterol trafficking. The brightness of this probe, which is ∼32-times greater than the widely used dehydroergosterol probe, is combined with resistance to photobleaching in solution and in human fibroblasts and an exceptionally large Stokes-like shift of ∼150-200 nm. The photophysical properties of the probe have been studied experimentally and computationally, suggesting an intersystem crossing to the triplet excited state with subsequent phosphorescent decay. Molecular dynamics simulations show a similar binding mode of cholesterol and the azasterol probe to NPC proteins, demonstrating the structural similarity of the probe to cholesterol.
开发具有改进性能的新型化学工具对于化学和细胞生物学至关重要。特别令人感兴趣的是开发具有重要细胞功能的小分子模拟物，以便直接观察它们在细胞中的运输。为此，设计并合成了一种新型15-氮杂甾醇作为发光胆固醇模拟物，用于监测胆固醇运输。该探针的亮度比广泛使用的脱氢麦角甾醇探针高约32倍，同时在溶液和人成纤维细胞中具有抗光漂白性能，以及异常大的约150 - 200 nm的斯托克斯样位移。通过实验和计算研究了该探针的光物理性质，表明其通过系间窜越到三重激发态并随后发生磷光衰减。分子动力学模拟显示胆固醇和氮杂甾醇探针对NPC蛋白具有相似的结合模式，证明了该探针与胆固醇的结构相似性。
