Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Effects of anions on the electrospray ionization of proteins in strong acids
Analyst ( IF 3.6 ) Pub Date : 2024-08-09 , DOI: 10.1039/d4an00421c Zhongbao Han 1 , Huizi Zheng 1 , Shuyao Wu 2 , Liyan Liu 1 , Lee Chuin Chen 3
Analyst ( IF 3.6 ) Pub Date : 2024-08-09 , DOI: 10.1039/d4an00421c Zhongbao Han 1 , Huizi Zheng 1 , Shuyao Wu 2 , Liyan Liu 1 , Lee Chuin Chen 3
Affiliation
|
The effect of anions on the positive electrospray ionization (ESI) of proteins in different strong acids with varying pH values from 3 to 1 is studied using high-pressure ESI. Reducing the pH from ∼2 to 1 caused a drastic shift in charge state from a high-charge-state distribution (HCSD) to a narrow low-charge-state distribution (LCSD). The shift in charge state was consistent with the circular dichroism result that showed a conformational change due to the “acid-induced folding” of proteins from an unfolding state to a compact molten globule state. Acids of different anions produced noticeable differences in the average charge for HCSD and LCSD. For HCSD, the average charge was lower than the value typically observed using formic and acetic acids. As for LCSD, the average charge was lower than the “native” charge. The high abundance of acid anion that induces the protein compaction was believed to play a role in charge reduction. The effectiveness of anions to “refold” a highly unfolded protein to a compact state and the propensity to reduce the charge of HCSD for proteins appeared to follow the selectivity series of anions towards the stationary phase in ion chromatography. However, the propensity of anions to reduce the charge for LCSD follows quite an opposite trend. The presence of ammonium salt in the acidic solution was found to increase the charge of LCSD. The simple mass spectrum with a narrow distribution of charge state obtained with perchloric acid at pH 1 was demonstrated to facilitate the counting of basic sites.
中文翻译：
阴离子对强酸中蛋白质电喷雾电离的影响
使用高压 ESI 研究了阴离子对 pH 值从 3 到 1 的不同强酸中的蛋白质的正电喷雾电离 (ESI) 的影响。将 pH 从 ∼2 降低至 1 导致电荷态从高电荷态分布 (HCSD) 急剧转变为窄的低电荷态分布 (LCSD)。电荷状态的转变与圆二色性结果一致，圆二色性结果显示由于蛋白质从展开状态到致密熔球状态的“酸诱导折叠”而导致构象变化。不同阴离子的酸对 HCSD 和 LCSD 的平均电荷产生显着差异。对于 HCSD，平均电荷低于通常使用甲酸和乙酸观察到的值。至于康乐及文化事务署，平均收费较「本地」收费为低。诱导蛋白质压缩的高丰度酸性阴离子被认为在电荷减少中发挥作用。阴离子将高度未折叠的蛋白质“重新折叠”至致密状态的有效性以及减少蛋白质的 HCSD 电荷的倾向似乎遵循离子色谱中阴离子对固定相的选择性系列。然而，阴离子减少康乐及文化事务署电荷的倾向则呈现出截然相反的趋势。发现酸性溶液中铵盐的存在会增加 LCSD 的电荷。证明用高氯酸在 pH 1 下获得的具有窄电荷态分布的简单质谱有助于碱性位点的计数。
更新日期：2024-08-09
中文翻译：
阴离子对强酸中蛋白质电喷雾电离的影响
使用高压 ESI 研究了阴离子对 pH 值从 3 到 1 的不同强酸中的蛋白质的正电喷雾电离 (ESI) 的影响。将 pH 从 ∼2 降低至 1 导致电荷态从高电荷态分布 (HCSD) 急剧转变为窄的低电荷态分布 (LCSD)。电荷状态的转变与圆二色性结果一致，圆二色性结果显示由于蛋白质从展开状态到致密熔球状态的“酸诱导折叠”而导致构象变化。不同阴离子的酸对 HCSD 和 LCSD 的平均电荷产生显着差异。对于 HCSD，平均电荷低于通常使用甲酸和乙酸观察到的值。至于康乐及文化事务署，平均收费较「本地」收费为低。诱导蛋白质压缩的高丰度酸性阴离子被认为在电荷减少中发挥作用。阴离子将高度未折叠的蛋白质“重新折叠”至致密状态的有效性以及减少蛋白质的 HCSD 电荷的倾向似乎遵循离子色谱中阴离子对固定相的选择性系列。然而，阴离子减少康乐及文化事务署电荷的倾向则呈现出截然相反的趋势。发现酸性溶液中铵盐的存在会增加 LCSD 的电荷。证明用高氯酸在 pH 1 下获得的具有窄电荷态分布的简单质谱有助于碱性位点的计数。
京公网安备 11010802027423号