On the liquid demixing of water + elastin-like polypeptide mixtures: bimodal re-entrant phase behaviour
On the liquid demixing of water + elastin-like polypeptide mixtures: bimodal re-entrant phase behaviour
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关于水弹性蛋白样多肽混合物的液体分层：双峰重入相行为
DOI：
10.1039/d0cp05013j
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发表时间：
2021
影响因子：
3.3
通讯作者：
Galindo, Amparo
中科院分区：
文献类型：
--
作者：
Lindeboom, Tom;Zhao, Binwu;Jackson, George;Hall, Carol K.;Galindo, Amparo
水+弹性蛋白样多肽（ELPs）表现出一个过渡温度，在此温度以下，链从崩溃状态转变为膨胀状态，让人想起蛋白质的冷变性。这种构象变化与液-液相分离相一致。统计热力学理论用于模拟ELPs在水溶液中的液相行为，并推断其在环境条件下的压力范围内的行为。在低压下，发现了闭环液-液平衡相行为，这与其他氢键溶剂+聚合物混合物的相行为一致。在深海环境的压力下，液-液不混相被预测为两个较低的临界溶液温度（LCSTs）。随着压力的进一步增大，系统呈现出两个独立的液-液平衡闭环区域。双峰lst和两个可再入LLE区域的观测预示着一种新的二元全局相图：type XII。在高elp浓度下，预测相图类似于蛋白质压力变性图；在低浓度下观察到可能的“熔融球状”状态。
Water + elastin-like polypeptides (ELPs) exhibit a transition temperature below which the chains transform from collapsed to expanded states, reminiscent of the cold denaturation of proteins. This conformational change coincides with liquid–liquid phase separation. A statistical-thermodynamics theory is used to model the fluid-phase behavior of ELPs in aqueous solution and to extrapolate the behavior at ambient conditions over a range of pressures. At low pressures, closed-loop liquid–liquid equilibrium phase behavior is found, which is consistent with that of other hydrogen-bonding solvent + polymer mixtures. At pressures evocative of deep-sea conditions, liquid–liquid immiscibility bounded by two lower critical solution temperatures (LCSTs) is predicted. As pressure is increased further, the system exhibits two separate regions of closed-loop of liquid–liquid equilibrium (LLE). The observation of bimodal LCSTs and two re-entrant LLE regions herald a new type of binary global phase diagram: Type XII. At high-ELP concentrations the predicted phase diagram resembles a protein pressure denaturation diagram; possible “molten-globule”-like states are observed at low concentration.