Investigating the Role of Adducts in Protein Supercharging with Sulfolane
Investigating the Role of Adducts in Protein Supercharging with Sulfolane
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DOI：
10.1007/s13361-011-0319-1
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发表时间：
2012-03-01
影响因子：
3.2
通讯作者：
Venter, Andre R.
中科院分区：
文献类型：
--
作者：
Douglass, Kevin Aart;Venter, Andre R.
研究了在不考虑构象效应的情况下，环丁砜对细胞色素c（cyt c）的电喷雾电离质谱（ESI-MS）增压效应。向细胞色素c的变性溶液中加入1 mM或更高数量级的环丁砜，导致在0.1至10 μ M范围内不依赖于蛋白质浓度的增压。虽然在正模式下观察到增压，但在负模式下观察到电荷态分布没有变化，排除了极性无关的因素，如构象变化或表面张力效应。观察到一系列环丁砜加合物的强度随着电荷状态的增加而增加，这表明环丁砜与细胞色素c的带电位点之间的直接相互作用在增压中发挥着重要作用。我们建议，通过大规模的偶极重排发生的电荷离域的高极性增压试剂减少了静电势垒的近端充电沿着的cyt c氨基酸链。支持这一主张，增压被证明是增加与结构上与环丁砜相关的几个增压试剂的偶极矩。
The supercharging effect of sulfolane on cytochrome c (cyt c) during electrospray ionization mass spectrometry (ESI-MS) in the absence of conformational effects was investigated. The addition of sulfolane on the order of 1 mM or greater to denaturing solutions of cyt c results in supercharging independent of protein concentration over the range of 0.1 to 10 mu M. While supercharging was observed in the positive mode, no change in the charge state distribution was observed in the negative mode, ruling out polarity-independent factors such as conformational changes or surface tension effects. A series of sulfolane adducts observed with increasing intensity concurrent with increasing charge state suggests that a direct interaction between sulfolane and the charged sites of cyt c plays an important role in supercharging. We propose that charge delocalization occurring through large-scale dipole reordering of the highly polar supercharging reagent reduces the electrostatic barrier for proximal charging along the cyt c amino acid chain. Supporting this claim, supercharging was shown to increase with increasing dipole moment for several supercharging reagents structurally related to sulfolane.