Islam Mullah Muhaiminul, Moyon N Shaemningwar, Gashnga Pynsakhiat Miki, Mitra Sivaprasad
UGC Center for Advanced Studies, Department of Chemistry, North-Eastern Hill University, Shillong, 793 022, India.
J Fluoresc. 2014 Mar;24(2):579-88. doi: 10.1007/s10895-013-1330-7. Epub 2013 Nov 28.
The binding behavior of antibacterial drug sulfadiazine (SDZ) with water soluble globular proteins like bovine as well as human serum albumin (BSA and HSA, respectively) and lysozyme (LYS) was monitored by fluorescence titration and molecular docking calculations. The experimental data reveal that the quenching of the intrinsic protein fluorescence in presence of SDZ is due to the strong interaction in the drug binding site of the respective proteins. The Stern-Volmer plot shows positive deviation at higher quencher concentration for all the proteins and was explained in terms of a sphere of action model. The calculated fluorophore-quencher distances vary within 4 ~ 11 Å in different cases. Fluorescence experiments at different temperature indicate thermodynamically favorable binding of SDZ with the proteins with apparently strong association constant (~10(4)-10(5) M(-1)) and negative free energy of interaction within the range of -26.0 ~ -36.8 kJ mol(-1). The experimental findings are in good agreement with the respective parameters obtained from best energy ranked molecular docking calculation results of SDZ with all the three proteins.
通过荧光滴定和分子对接计算监测了抗菌药物磺胺嘧啶（SDZ）与水溶性球状蛋白如牛血清白蛋白和人血清白蛋白（分别为BSA和HSA）以及溶菌酶（LYS）的结合行为。实验数据表明，在SDZ存在下，蛋白质固有荧光的猝灭是由于药物与各蛋白质结合位点之间的强相互作用。斯特恩-沃尔默图显示，在较高猝灭剂浓度下，所有蛋白质均出现正偏差，并用作用球模型进行了解释。在不同情况下，计算得到的荧光团-猝灭剂距离在4至11埃之间变化。不同温度下的荧光实验表明，SDZ与蛋白质的结合在热力学上是有利的，其结合常数明显较强（约10⁴-10⁵ M⁻¹），相互作用自由能为-26.0至-36.8 kJ mol⁻¹。实验结果与从SDZ与所有三种蛋白质的最佳能量排序分子对接计算结果中获得的相应参数高度一致。
