Conformations, unfolding, and refolding of apomyoglobin in vacuum: An activation barrier for gas-phase protein folding
Conformations, unfolding, and refolding of apomyoglobin in vacuum: An activation barrier for gas-phase protein folding
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DOI：
10.1021/ja962914k
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发表时间：
1997-04-02
影响因子：
15
通讯作者：
Jarrold, MF
中科院分区：
文献类型：
--
作者：
Shelimov, KB;Jarrold, MF
气相离子迁移率测量已被用来表征构象的+4至+22电荷状态的脱辅基肌红蛋白。对于+8至+10电荷状态，通过电喷雾pH值接近3的溶液产生，两个相对紧凑的构象被解析，这可能反映了溶液中蛋白质的状态。当碰撞加热时，这些相对紧凑的构象展开成更延伸的构象。对于高（>+10）电荷状态，仅观察到扩展构象，并且随着电荷增加，它们变得更加扩展。较高（>+7）电荷态的质子剥离以产生+4至+7电荷态导致自发塌缩成部分折叠构象。进一步折叠后，观察到碰撞加热的塌陷结构，表明在气相中的蛋白质折叠的激活障碍的存在。这种势垒可能是库仑排斥和二级结构重组的结果。对于低（
Gas-phase ion mobility measurements have been used to characterize the conformations of the +4 to +22 charge states of apomyoglobin. For the +8 to +10 charge states, generated by electrospraying pH approximate to 3 solutions, two relatively compact conformations were resolved which may reflect the state of the protein in solution. These relatively compact conformations unfold into more extended conformations when collisionally heated. Only extended conformations are observed for the high (>+10) charge states, and they become more extended as the charge increases. Proton stripping of the higher (>+7) charge states to produce the +4 to +7 charge states results in spontaneous collapse into partially folded conformations. Further folding is observed upon collisional heating of the collapsed structures, indicating the presence of an activation barrier for protein folding in the gas phase. The barrier probably results from Coulomb repulsion and the reorganization of secondary structure. For the lower (