Temperature and pH dependences of hydrogen exchange and global stability for ovomucoid third domain.
Temperature and pH dependences of hydrogen exchange and global stability for ovomucoid third domain.
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卵类粘蛋白第三结构域氢交换和整体稳定性的温度和 pH 依赖性。
DOI：
10.1021/bi9517603
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发表时间：
1996
期刊：
影响因子：
2.9
通讯作者：
Robertson,AD
中科院分区：
文献类型：
--
作者：
Swint-Kruse,L;Robertson,AD
用二维核磁共振波谱监测了火鸡卵粘蛋白第三结构域中30多个残基的质子−重离子交换率(KOBS)。为了测试交换是否受全局去折叠的控制，在已知去折叠自由能变化的广泛pH和温度范围内测量了速率[Swint，L.，&Robertson，A.D.(1993)蛋白质科学]。2,2037−2049；Swint-Kruse，L.和Robertson，A.D.(1995年)生物化学34,4724−4732]。在观察到EX2动力学的条件下，6个−11残基的子集与全局稳定性表现出一对一的相关性。这些残基都位于二级结构的中心区域。许多其他网站显示出不同程度的关联，而一些网站仅在基础上比预期的要慢。初步证据表明，后者是由于偏离了EX2动力学，尽管与观察到的牛胰腺胰蛋白酶抑制剂的偏离相比，实验条件相对温和(pH*3和40°C)。这些结果，再加上对蛋清溶菌酶和棕榈酸酶的类似观察，表明在解释交换研究时不应假设EX2动力学。
Two-dimensional nuclear magnetic resonance spectroscopy has been used to monitor proton−deuterium exchange rates (kobs) for more than 30 residues in turkey ovomucoid third domain. To test whether exchange is governed by global unfolding, rates were measured over a wide range of pH and temperatures where the change in the free energy of unfolding ( ) is known [Swint, L., & Robertson, A. D. (1993)Protein Sci. 2, 2037−2049; Swint-Kruse, L., & Robertson, A. D. (1995)Biochemistry34,4724−4732]. Under conditions where EX2 kinetics are observed, a subset of 6−11 residues exhibits a one-to-one correlation with global stability. These residues are all located in central regions of secondary structures. Many other sites show varied degrees of correlation with , while some are slower than expected on the basis of alone. Preliminary evidence suggests that the latter is due to deviation from EX2 kinetics, even though experimental conditions are relatively mild (pH* 3 and 40 °C) compared to those in which deviations were observed for bovine pancreatic trypsin inhibitor. These results, together with similar observations for hen egg white lysozyme and barnase, suggest that EX2 kinetics should not be assumed when interpreting exchange studies.