Shukla Nimesh, Pomarico Enrico, Hecht Cody J S, Taylor Erika A, Chergui Majed, Othon Christina M
Department of Physics, Wesleyan University, Middletown, CT 06457, USA.
Laboratoire de Spectroscopie Ultrarapide (LSU) and Lausanne Centre for Ultrafast Science (LACUS), École Polytechnique Fédérale de Lausanne, ISIC, FSB, CH-1015 Lausanne, Switzerland.
Arch Biochem Biophys. 2018 Feb 1;639:38-43. doi: 10.1016/j.abb.2017.12.013. Epub 2017 Dec 26.
Sucralose is a commonly employed artificial sweetener that appears to destabilize protein native structures. This is in direct contrast to the bio-preservative nature of its natural counterpart, sucrose, which enhances the stability of biomolecules against environmental stress. We have further explored the molecular interactions of sucralose as compared to sucrose to illuminate the origin of the differences in their bio-preservative efficacy. We show that the mode of interactions of sucralose and sucrose in bulk solution differ subtly through the use of hydration dynamics measurement and computational simulation. Sucralose does not appear to disturb the native state of proteins for moderate concentrations (<0.2 M) at room temperature. However, as the concentration increases, or in the thermally stressed state, sucralose appears to differ in its interactions with protein leading to the reduction of native state stability. This difference in interaction appears weak. We explored the difference in the preferential exclusion model using time-resolved spectroscopic techniques and observed that both molecules appear to be effective reducers of bulk hydration dynamics. However, the chlorination of sucralose appears to slightly enhance the hydrophobicity of the molecule, which reduces the preferential exclusion of sucralose from the protein-water interface. The weak interaction of sucralose with hydrophobic pockets on the protein surface differs from the behavior of sucrose. We experimentally followed up upon the extent of this weak interaction using isothermal titration calorimetry (ITC) measurements. We propose this as a possible origin for the difference in their bio-preservative properties.
三氯蔗糖是一种常用的人工甜味剂，它似乎会破坏蛋白质的天然结构。这与其天然对应物蔗糖的生物保鲜性质形成直接对比，蔗糖可增强生物分子抵抗环境压力的稳定性。我们进一步探究了三氯蔗糖与蔗糖的分子相互作用，以阐明它们生物保鲜功效差异的根源。通过水合动力学测量和计算模拟，我们发现三氯蔗糖和蔗糖在本体溶液中的相互作用模式存在细微差异。在室温下，对于中等浓度（<0.2 M）的三氯蔗糖，它似乎不会干扰蛋白质的天然状态。然而，随着浓度增加或处于热应激状态时，三氯蔗糖与蛋白质的相互作用似乎有所不同，导致天然状态稳定性降低。这种相互作用的差异似乎很微弱。我们使用时间分辨光谱技术探究了优先排除模型中的差异，发现这两种分子似乎都是本体水合动力学的有效降低剂。然而，三氯蔗糖的氯化作用似乎略微增强了分子的疏水性，这减少了三氯蔗糖从蛋白质 - 水界面的优先排除。三氯蔗糖与蛋白质表面疏水口袋的弱相互作用不同于蔗糖的行为。我们使用等温滴定量热法（ITC）测量实验性地追踪了这种弱相互作用的程度。我们认为这可能是它们生物保鲜特性差异的一个原因。
