Solvation Behavior of Elastin-like Polypeptides in Divalent Metal Salt Solutions
Solvation Behavior of Elastin-like Polypeptides in Divalent Metal Salt Solutions
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DOI：
10.1021/acs.jpclett.3c02476
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发表时间：
2023-11-03
影响因子：
5.7
通讯作者：
van der Vegt，Nico F. A.
中科院分区：
文献类型：
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作者：
Zhao，Yani;Bharadwaj，Swaminath;van der Vegt，Nico F. A.
采用浊点测量、分子动力学模拟和红外光谱相结合的方法，研究了氯化钙和氯化镁对两种不同弹性蛋白样多肽的浊点温度的影响。二价金属阳离子水溶液中ELP的浊点变化主要由两种相互竞争的相互作用决定：阳离子-酰胺氧的静电相互作用和阳离子的水合作用。尤其是，Ca~(2+)离子更容易脱离其水化壳，通过形成离子桥直接与两个酰胺氧原子接触。相比之下，镁离子具有更强的水合能力，并倾向于与其水合壳层一起向胺氧基分配。事实上，虽然亲水性ELP V5A2G3在低浓度的氯化镁下盐析，但在较高的盐浓度下盐析。相反，由于桥联效应，CaCl2在较高的盐浓度下使ELP急剧盐析出溶液。
The effects of CaCl2and MgCl2on the cloud point temperature of two different elastin-like polypeptides (ELPs) were studied using a combination of cloud point measurements, molecular dynamics simulations, and infrared spectroscopy. Changes in the cloud point for the ELPs in aqueous divalent metal cation solutions were primarily governed by two competing interactions: the cation–amide oxygen electrostatic interaction and the hydration of the cation. In particular, Ca2+cations can more readily shed their hydration shells and directly contact two amide oxygens by the formation of ion bridges. By contrast, Mg2+cations were more strongly hydrated and preferred to partition toward the amide oxygens along with their hydration shells. In fact, although hydrophilic ELP V5A2G3was salted-out at low concentrations of MgCl2, it was salted-in at higher salt concentrations. By contrast, CaCl2salted the ELP sharply out of solution at higher salt concentrations because of the bridging effect.