Non-symbiotic hemoglobin conformational space dependence on the heme coordination using nESI-TIMS-TOF MS
Non-symbiotic hemoglobin conformational space dependence on the heme coordination using nESI-TIMS-TOF MS
复制标题
DOI：
10.1016/j.ijms.2018.03.008
复制
发表时间：
2018-07-01
影响因子：
1.8
通讯作者：
Fernandez-Lima, Francisco
中科院分区：
文献类型：
--
作者：
Butcher, David;Bernad, Sophie;Fernandez-Lima, Francisco
在这项研究中，第一次，水稻非共生血红蛋白1型（rHb 1）的构象空间作为一个功能的起始溶液的pH值进行了研究，使用捕获离子迁移谱耦合质谱（TIMS-MS）和分子动力学。电荷态分布，载脂蛋白的holo形式的比例，和碰撞截面（欧米茄）的配置文件作为溶液pH值的函数的比较显示更高的稳定性的rHb 1野生型（WT）相比，H73 L突变体在弱酸性条件下。Omega配置文件的rHb 1 WT和H73 L全息和载脂蛋白形式的比较表明，只有最初的展开途径涉及血红素腔，有和没有血红素损失，其次是展开途径不一定涉及血红素辅基的环境。候选结构中观察到的欧米茄配置文件中的9个转换，提出了使用分子动力学模拟的基础上欧米茄配置文件，紫外吸收光谱和圆二色性数据的方式来描述一个潜在的展开途径。所描述的解折叠途径表明，rHb 1解折叠是由A，B和H螺旋的初始距离驱动的，而血红素腔和血红素组保持完整，随后是E，F和G螺旋的距离和随后的α-螺旋结构的损失，导致最终的无规卷曲构象。(C)2018爱思唯尔B. V.保留所有权利。
In this study, for the first time, the conformational space of the rice non-symbiotic hemoglobin type 1 (rHb1) was studied as a function of the starting solution pH using trapped ion mobility spectrometry coupled to mass spectrometry (TIMS-MS) and molecular dynamics. Comparison of the charge state distribution, apo to holo form ratio, and the collision cross section (Omega) profiles as a function of the solution pH showed higher stability of the rHb1 wild-type (WT) when compared with the H73L mutant at mildly acidic conditions. Comparison of the Omega profiles of the rHb1 WT and H73L holo and apo form showed that only the initial unfolding pathways involved the heme cavity, with and without a heme loss, followed by unfolding pathways not necessarily involving the environment of the heme prosthetic group. Candidate structures for the nine transitions observed in the Omega profiles were proposed using molecular dynamic simulations based on the Omega profiles, UV absorption spectroscopy and circular dichroism data as way to describe a potential unfolding pathway. The described unfolding pathway suggests that the rHb1 unfolding is driven by initial distancing of the A, B, and H helices, while the heme cavity and heme group remains intact, followed by the distancing of the E, F, and G helices and subsequent loss of the alpha-helical structure leading to a final random coil conformation. (C) 2018 Elsevier B.V. All rights reserved.