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Dissociation of trivalent metal ion (Al 3 + , Ga 3 + , In 3 + and Rh 3 + )–peptide complexes under electron capture dissociation conditions
Author(s) -
Chen Xiangfeng,
Liu Guoqiang,
Elaine Wong Y. L.,
Deng Liulin,
Wang Ze,
Li Wan,
Dominic Chan T.W.
Publication year - 2016
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.7502
Subject(s) - chemistry , ion , dissociation (chemistry) , metal ions in aqueous solution , metal , electron capture dissociation , lanthanide , crystallography , fourier transform ion cyclotron resonance , organic chemistry
Rationale The electron capture dissociation (ECD) of proteins/peptides is affected by the nature of charge carrier. It has been reported that transition metal ions could tune the ECD pathway of peptides. To further explore the charge carrier effect of metal ions, ECD of peptides adducted with trivalent transition metal ions, including group IIIB (Al 3 + , Ga 3 + , and In 3 + ) and Rh 3 + , were investigated and compared with that of the lanthanide ion (Ln 3+ ). Methods Bradykinin‐derived peptides were used as model peptides to probe the dissociation pathways. The ECD experiments were performed on a Bruker APEX III 4.7T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. Results Typical c ‐/ z ‐ions with and without metal ions were observed in the ECD of peptides adducted with Group IIIB metal ions as charge carriers. Connection of non‐metalated c ‐ions and metalated z ‐ions at the position of the serine residue indicated that serine is one of the binding sites of the metal ion on the model peptides. Typical slow heating ions, including metalated a‐ / b ‐ions and non‐metalated y ‐ions, were generated in ECD of Rh 3 + ‐adducted peptides. Conclusions Based on the experimental results, it is proposed that (i) for Group IIIB metal ion‐peptide complexes, the incoming electron is captured by the proton in the salt‐bridge structures of precursor ions; (ii) for Rh 3 + ‐peptide complexes, the incoming electron is captured by the metal ion due to the formation of charge‐solvated precursor ions formed through arginine residue‐metal coordination. Our results indicate that the heterogeneity of precursor ions plays an important role for the ECD of metalated peptides. Copyright © 2016 John Wiley & Sons, Ltd.