蝌蚪状类弹性蛋白多肽相变特性分析

为研究不同盐类型及浓度对蝌蚪状ELPs₄₀相变特性的影响,探究霍夫曼斯特(Hofmeister)离子序中阴、阳离子对蝌蚪状ELPs₄₀相变温度的影响,通过设计、表达和纯化后,获得由谍标签/捕谍器(SpyTag/SpyCatcher),以及由40个重复的线性类弹性蛋白多肽所形成的2个蝌蚪型结构的ELPs₄₀.结果表明:蝌蚪状ELPs₄₀相变温度比ELPs₈₀相变温度高1.35 ℃;阴离子对蝌蚪状ELPs₄₀相变温度的影响符合Hofmeister离子序现象,但NH₄⁺,K⁺,Na⁺等阳离子却发生逆Hofmeister离子序现象;在NaCl,Na₂SO₄,NaNO₃,K₂SO₄,KCl,KNO₃,NH₄Cl,NH₄NO₃,(NH₄)₂SO₄等不同浓度缓冲液中,蝌蚪状ELPs₄₀发生相变所需的温度范围显著高于线性ELPs₄₀,这与其特殊的结构密切相关.

Phase Transition Behavior of Tadpole-Like Elastin-Like Polypeptides

In order to study the effects of different salt types and concentrations on the phase transition characteristics of elastin-like polypeptides 40(ELPs₄₀), the influence of the anions and cations in the Hofmeister on the phase transition temperature of ELPs₄₀ was investigated. After designing, expressing and purifying, the ELPs₄₀ with the SpyTag/SpyCatcher and two 40-repetitive linear elastin-like peptides were obtained. The results show that the phase transition temperature of ELPs₄₀ is higher with 1.35 ℃ than that of the ELPs₈₀. The effect of anions on the phase transition temperature of ELPs₄₀ accords with Hofmeister, but the cations such as NH₄⁺, K⁺, Na⁺ have inverse Hofmeister; in the buffers with different concentrations such as NaCl, Na₂SO₄, NaNO₃, K₂SO₄, KCl, KNO₃, NH₄Cl, NH₄NO₃,(NH₄)₂SO₄, etc., temperature range required for phase transition of the tadpole-like ELPs₄₀ is significantly higher than that of the linear ELPs₄₀, which should be closely related to its special structure.