Shrivastava Sandeep, Haldar Sourav, Gimpl Gerald, Chattopadhyay Amitabha
Centre for Cellular and Molecular Biology, Hyderabad, India.
J Phys Chem B. 2009 Apr 2;113(13):4475-81. doi: 10.1021/jp808309u.
Fluorescent analogues of cholesterol offer a powerful approach for monitoring cholesterol behavior in membranes because of their high sensitivity, suitable time resolution, and multiplicity of measurable parameters. In this work, we have monitored the orientation and dynamics of a novel fluorescent cholesterol probe, 6-dansylcholestanol (DChol), in membranes of different phase type utilizing sensitive fluorescence techniques including the red-edge excitation shift (REES) approach. Our results show that fluorescence emission maximum, anisotropy, and lifetime of DChol are dependent on the phase of the membrane. Interestingly, DChol exhibits significant red-edge excitation shift (REES) that appear to depend on the phase of the membrane. Analysis of membrane penetration depth by the parallax method shows that the dansyl group of DChol is localized at the interfacial region of the membrane ( approximately 15.6 A from the center of the bilayer). This is in excellent agreement with the previously reported location of cholesterol in fluid-phase membranes. We propose that DChol could be a potentially useful cholesterol analogue in future studies of model and biological membranes.
胆固醇的荧光类似物为监测膜中胆固醇行为提供了一种强大的方法，因为它们具有高灵敏度、合适的时间分辨率以及多种可测量参数。在这项工作中，我们利用包括红边激发位移（REES）方法在内的灵敏荧光技术，监测了一种新型荧光胆固醇探针6-丹磺酰胆固醇（DChol）在不同相类型膜中的取向和动力学。我们的结果表明，DChol的最大荧光发射、各向异性和寿命取决于膜的相。有趣的是，DChol表现出明显的红边激发位移（REES），这似乎取决于膜的相。通过视差法对膜穿透深度的分析表明，DChol的丹磺酰基团位于膜的界面区域（距双层中心约15.6埃）。这与先前报道的胆固醇在液相膜中的位置非常吻合。我们提出，在未来对模型膜和生物膜的研究中，DChol可能是一种潜在有用的胆固醇类似物。
