Singh Rupashree Balia, Mahanta Subrata, Guchhait Nikhil
University of Calcutta, Department of Chemistry, 92 A.P.C. Road, Kolkata 700009, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Jun;72(5):1103-11. doi: 10.1016/j.saa.2009.01.011. Epub 2009 Jan 24.
Interaction of charge transfer fluorophore N,N-dimethylaminonaphthyl-(acrylo)-nitrile (DMANAN) with globular proteins Human Serum Albumin (HSA) and Bovine Serum Albumin (BSA) brings forth a marked change in the position and intensity of band maxima both in case of absorption and fluorescence spectra. Spectroscopic approach has been elaborately implemented to explore the binding phenomena of the probe with HSA and BSA and it is found that the extent of binding of the probe to both serum albumins is similar in nature. Steady state fluorescence anisotropy values, fluorescence quenching study using acrylamide quencher and Red Edge Excitation Shift (REES) help in drawing reliable conclusions regarding the location of the probe molecule within the hydrophobic cavity of the proteins. An increase in fluorescence lifetime of the probe molecule solubilized in both the proteinous media also indicate that the probe is located at the motionally restricted environment inside the hydrophobic cavity of proteins and hence non-radiative channels are less operative than in the bulk water. Similarly, the variation of position and intensity of the emission maxima of DMANAN solubilized in micellar medium of Sodium Dodecyl Sulphate (SDS) also predicts well the critical micellar concentration (CMC) and polarity of micellar microenvironment.
电荷转移荧光团N,N-二甲基氨基萘基-(丙烯酰基)-腈(DMANAN)与球状蛋白人血清白蛋白(HSA)和牛血清白蛋白(BSA)相互作用，在吸收光谱和荧光光谱中，谱带最大值的位置和强度均发生显著变化。已精心采用光谱方法来探究该探针与HSA和BSA的结合现象，结果发现该探针与两种血清白蛋白的结合程度在本质上相似。稳态荧光各向异性值、使用丙烯酰胺猝灭剂的荧光猝灭研究以及红边激发位移(REES)有助于就探针分子在蛋白质疏水腔内的位置得出可靠结论。溶解在两种蛋白质介质中的探针分子的荧光寿命增加也表明，该探针位于蛋白质疏水腔内运动受限的环境中，因此非辐射通道的作用比在大量水中小。同样，溶解在十二烷基硫酸钠(SDS)胶束介质中的DMANAN发射最大值的位置和强度变化也很好地预测了临界胶束浓度(CMC)和胶束微环境的极性。
