Supermetallization of peptides and proteins during electrospray ionization.
The formation of metal-peptide complexes during electrospray ionization (ESI) is a widely known phenomenon and is often considered to be undesirable. Such effect considerably limits the use of ESI mass spectrometry for the investigation of biologically relevant metal-peptide compounds that are present in the solution and play critical roles in many bioprocesses such as progression of neurodegenerative diseases. In the article, it is demonstrated that under specific conditions such as high temperature of the desolvating capillary, an interesting effect, which can be called as 'supermetallization', occurs. Using a model peptide Αβ amyloid domain 1-16, it was observed that an increase in the temperature of the desolvating capillary results in multiple substitutions of hydrogen atoms by Zn atoms in this peptide. At high temperatures (T ~ 400 °C), up to 11 zinc atoms can be covalently bound to (1-16) Αβ. It was observed that supermetallization of (1-16) Αβ depends on the solvent composition and pH. Supermetallization was also demonstrated for proteins, such as ubiquitin and cytochrome C. That proves that the supermetallization is a general phenomenon for peptides and proteins. For the structural investigation of supermetallized complexes, electron-capture dissociation (ECD) fragmentation was applied. The effect of hydrogen rearranging during ECD was observed. In addition, quantum chemical calculations were used to estimate the possible structures of different supermetallized complexes. These results allow a more deep understanding of the limitations of the use of ESI mass spectrometry for the investigation of biologically relevant metal-peptide complexes. Copyright © 2015 John Wiley & Sons, Ltd.
Skolkovo Institute of Science and Technology, Novaya St., 100, Skolkovo, 143025, Russia.|Institute for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr. 38 k.2, 119334, Moscow, Russia.|Moscow Institute of Physics and Technology, 141700 Dolgoprudnyi, Moscow, Russia.
Yury
Y
Kostyukevich
Institute for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr. 38 k.2, 119334, Moscow, Russia.|Moscow Institute of Physics and Technology, 141700 Dolgoprudnyi, Moscow, Russia.
Alexey
A
Kononikhin
Emanuel Institute for Biochemical Physics, Russian Academy of Sciences, Kosygina st. 4, 119334, Moscow, Russia.|Moscow Institute of Physics and Technology, 141700 Dolgoprudnyi, Moscow, Russia.|Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
Igor
I
Popov
Institute for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr. 38 k.2, 119334, Moscow, Russia.|Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
Maria
M
Indeykina
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
Sergey A
SA
Kozin
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
Alexander A
AA
Makarov
Skolkovo Institute of Science and Technology, Novaya St., 100, Skolkovo, 143025, Russia.|Institute for Energy Problems of Chemical Physics, Russian Academy of Sciences, Leninskij pr. 38 k.2, 119334, Moscow, Russia.|Moscow Institute of Physics and Technology, 141700 Dolgoprudnyi, Moscow, Russia.
Eugene
E
Nikolaev
ESI; FT ICR; amyloid; mass spectrometry; metal ions; metal-peptide complexes