Increasing Ubiquitin Ion Resistance to Unfolding in the Gas Phase Using Chloride Adduction: Preserving More “Native-Like” Conformations Despite Collisional Activation

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• 作者：Nicole D. Wagner ; Doyong Kim ; David H. Russell
• 刊名：Analytical Chemistry
• 出版年：2016
• 出版时间：June 7, 2016
• 年：2016
• 卷：88
• 期：11
• 页码：5934-5940
• 全文大小：417K
• 年卷期：0
• ISSN：1520-6882

文摘

Electrospray ionization (ESI) of ubiquitin from acidified (0.1%) aqueous solution produces abundant ubiquitin–chloride adduct ions, [M + nH + xCl]^(n – x)+, that upon mild heating react via elimination of neutral HCl. Ion mobility collision cross section (CCS) measurements show that ubiquitin ions retaining chloride adducts exhibit CCS values similar to those of the “native-state” of the protein. Coupled with results from recent molecular dynamics (MD) simulations for the evolution of a salt-containing electrospray droplet, this study provides a more complete picture for how the presence of salts affects the evolution of protein conformers in the final stages of dehydration of the ESI process and within the instrument.