Effects of cations on protein and peptide charging in electrospray ionization from aqueous solutions.
Effects of cations on protein and peptide charging in electrospray ionization from aqueous solutions.
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DOI：
10.1007/s13361-014-0864-5
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发表时间：
2014-06
影响因子：
3.2
通讯作者：
Williams, Evan R.
中科院分区：
文献类型：
--
作者：
Susa, Anna C.;Mortensen, Daniel N.;Williams, Evan R.
关键词：
报道了离子半径在69~337 pm之间的8种不同阳离子对电喷雾电离多肽和蛋白质的影响。除NH4+外，所有阳离子都发生了显著的加合作用，与不加盐的溶液相比，从含盐溶液中形成的平均蛋白质电荷更低。圆二色谱和离子迁移率结果表明，蛋白质在纯水和盐溶液中的构象不同，这可能影响了带电的程度。Li+和Cs+溶液形成的蛋白质和多肽离子的平均电荷相似，它们的Gibbs溶剂化自由能(GSFE)相差225kJ/mol。低电荷态通常是由具有较低GSFE值的四甲基铵和四乙基铵溶液形成的。当被加成的蛋白质离子被碰撞激活时，具有最低GSFE的较大阳离子很容易丢失，从而形成较低的分析物电荷态。该反应途径为在天然质谱学条件下产生丰富的单质子化蛋白质离子提供了一条途径。蛋白质和多肽对NH4+的平均电荷与对Rb+和K+的平均电荷基本相同，而Rb+和K+的GSFE和离子半径相似。这表明在自然质谱学中，质子从NH4+转移到蛋白质中对蛋白质带电程度的影响不大。
The effects of eight different cations with ionic radii between 69 and 337 pm on the charging of peptides and proteins with electrospray ionization from aqueous acetate salt solutions are reported. Significant adduction occurs for all cations except NH4+, and the average protein charge is lower when formed from solutions containing salts compared to solutions without salts added. Circular dichroism and ion mobility results show the protein conformations are different in pure water compared to salt solutions, which likely affects the extent of charging. The average charge of protein and peptide ions formed from solutions with Li+ and Cs+, which have Gibbs solvation free energies (GSFEs) that differ by 225 kJ/mol, is similar. Lower charge states are typically formed from solutions with tetramethylammonium and tetraethylammonium that have lower GSFE values. Loss of the larger cations that have the lowest GSFEs is facile when adducted protein ions are collisionally activated resulting in the formation of lower analyte charge states. This reaction pathway provides a route to produce abundant singly protonated protein ions under native mass spectrometry conditions. The average protein and peptide charge with NH4+ is nearly the same as that with Rb+ and K+, cations with similar GSFE and ionic radii. This indicates that proton transfer from NH4+ to proteins plays an insignificant role in the extent of protein charging in native mass spectrometry.
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影响因子：
--
作者：
DZIDIC, I;KEBARLE, P
通讯作者：
KEBARLE, P
DOI：
10.1007/s13361-012-0393-z
发表时间：
2012-07-01
影响因子：
3.2
作者：
Hall, Zoe;Robinson, Carol V.
通讯作者：
Robinson, Carol V.
影响因子：
15
作者：
HU, PF;GROSS, ML
通讯作者：
GROSS, ML
影响因子：
7.4
作者：
Flick, Tawnya G.;Cassou, Catherine A.;Chang, Terrence M.;Williams, Evan R.
通讯作者：
Williams, Evan R.
影响因子：
64.8
作者：
Duft, D;Achtzehn, T;Leisner, T
通讯作者：
Leisner, T