A new strategy to determine the protein mutation site using matrix-assisted laser desorption ionization in-source decay: derivatization by ionic liquid.
Matrix-assisted laser desorption ionization (MALDI) time-of-flight mass spectrometry (TOF-MS) can be considered as state of the art in the field of proteins and peptides analysis. In this work, we have designed an ionic liquid derivative strategy to obtain abundant fragment ions in MALDI in-source decay (ISD) and used the analysis of angiogenin with mutation in the fortieth (K40I) as an instance. Firstly, we have synthesized two types of ionic liquids, 3-allyl-4-methyl-1H-imidazol-3-ium and 4-methyl-3-(pent-4-yn-1-yl)-1H-imidazol-3-ium. Then in the light-catalyzed reaction, the alkenyl ionic liquid can open the disulfide bond of K40I protein and add to the thiol. And the derived protein can process in-source decay under the effect of ionic liquid group to produce c-z type ions. Additionally this fragmentation is potentiated to support widely range of fragment ions which can cover the location of mutation. Our results have supplied a new top-down method about how to analyze the mutation or even post-translational modification of proteins in MALDI mass spectrometry.
Department of Chemistry, Zhejiang University, Hangzhou 310027, China; Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China; Department of Pharmaceutical Analysis, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China.
Mengzhe
M
Guo
Research Center of Molecular Medicine, Zhejiang University School of Medicine, Hangzhou 310058, China.
Yixing
Y
Zhai
Cancer Institute, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China.
Cheng
C
Guo
Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Yaqin
Y
Liu
Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China; Department of Pharmaceutical Analysis, Xuzhou Medical College, Xuzhou, Jiangsu 221004, China.
Daoquan
D
Tang
Department of Chemistry, Zhejiang University, Hangzhou 310027, China. Electronic address: panyuanjiang@zju.edu.cn.
Yuanjiang
Y
Pan
D052578:Ionic Liquids / Q000737:chemistry*; D015394:Molecular Structure; D009154:Mutation; D011506:Proteins / Q000032:analysis / Q000737:chemistry* / Q000235:genetics*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D052578:Ionic Liquids; D011506:Proteins
Angiogenin; Derivatization; In-source decay; Ionic liquid