Kinetic intermediates in the folding of gaseous protein ions characterized by electron capture dissociation mass spectrometry
Kinetic intermediates in the folding of gaseous protein ions characterized by electron capture dissociation mass spectrometry
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DOI：
10.1021/ja003143u
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发表时间：
2001-10-10
影响因子：
15
通讯作者：
McLafferty, FW
中科院分区：
文献类型：
--
作者：
Horn, DM;Breuker, K;McLafferty, FW
另一种机制提出，蛋白质在溶液中的折叠要么通过特定的专有中间体进行，要么通过“折叠漏斗”中的多种途径进行。用一种新的方法在气相中研究这些问题，该方法提供了无溶剂蛋白质离子的非共价结合的细节。多电荷阳离子对电子的俘获会导致主干键的立即解离(ECD)，但对非共价键的激发可以忽略不计；因此，线性蛋白质离子的ECD只有在这些离子不是通过非共价键结合在一起的情况下才会产生两个可测量的碎片离子。细胞色素c的9+离子的热展开通过多达13个主干区域(以44个键断裂为代表)的单独展开进行，熔化温度为
Alternative mechanisms propose that protein folding in solution proceeds either through specific obligate intermediates or by a multiplicity of routes in a "folding funnel". These questions are examined in the gas phase by using a new method that provides details of the noncovalent binding of solvent-free protein ions. Capture of an electron by a multiply charged cation causes immediate dissociation (ECD) of a backbone bond, but with negligible excitation of noncovalent bonds; thus ECD of a linear protein ion produces two measurable fragment ions only if these are not held together by noncovalent bonds. Thermal unfolding of 9+ ions of cytochrome c proceeds through the separate unfolding of up to 13 backbone regions (represented by 44 bond cleavages) with melting temperatures of