1
|
Gopakumar G, Svensson PHW, Grånäs O, Brena B, Schwob L, Unger I, Saak CM, Timm M, Bülow C, Kubin M, Zamudio-Bayer V, Lau JT, von Issendorff B, Abid AR, Lindblad A, Danielsson E, Koerfer E, Caleman C, Björneholm O, Lindblad R. X-ray Induced Fragmentation of Protonated Cystine. J Phys Chem A 2022; 126:1496-1503. [PMID: 35213156 PMCID: PMC8919253 DOI: 10.1021/acs.jpca.1c10158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We demonstrate site-specific X-ray induced fragmentation across the sulfur L-edge of protonated cystine, the dimer of the amino acid cysteine. Ion yield NEXAFS were performed in the gas phase using electrospray ionization (ESI) in combination with an ion trap. The interpretation of the sulfur L-edge NEXAFS spectrum is supported by Restricted Open-Shell Configuration Interaction (ROCIS) calculations. The fragmentation pathway of triply charged cystine ions was modeled by Molecular Dynamics (MD) simulations. We have deduced a possible pathway of fragmentation upon excitation and ionization of S 2p electrons. The disulfide bridge breaks for resonant excitation at lower photon energies but remains intact upon higher energy resonant excitation and upon ionization of S 2p. The larger fragments initially formed subsequently break into smaller fragments.
Collapse
Affiliation(s)
- Geethanjali Gopakumar
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Pamela H W Svensson
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Oscar Grånäs
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Barbara Brena
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Lucas Schwob
- Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, DE-22607 Hamburg, Germany
| | - Isaak Unger
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Clara-Magdalena Saak
- Department of Physical Chemistry, University of Vienna, Währingerstraßze 42, 1090 Vienna, Austria
| | - Martin Timm
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, DE-10623 Berlin, Germany
| | - Christine Bülow
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, DE-79104 Freiburg, Germany
| | - Markus Kubin
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany
| | - Vicente Zamudio-Bayer
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany
| | - J Tobias Lau
- Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, DE-79104 Freiburg, Germany
| | - Bernd von Issendorff
- Physikalisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 3, DE-79104 Freiburg, Germany
| | - Abdul R Abid
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.,Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P.O. Box 3000, 90570 Oulu, Finland
| | - Andreas Lindblad
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Emma Danielsson
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Ebba Koerfer
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Carl Caleman
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.,Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, DE-22607 Hamburg, Germany
| | - Olle Björneholm
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Rebecka Lindblad
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.,Abteilung für Hochempfindliche Röntgenspektroskopie, Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Strasse 15, DE-12489 Berlin, Germany.,Department of Physics, Lund University, Box 118, SE-22100 Lund, Sweden.,Department of Chemistry - Ångström Laboratory, Uppsala University, Box 538, SE-75121 Uppsala, Sweden
| |
Collapse
|
3
|
Zamora RA, Fuentes-Lemus E, Barrias P, Herrera-Morande A, Mura F, Guixé V, Castro-Fernandez V, Rojas T, López-Alarcón C, Aguirre P, Rivas-Aravena A, Aspée A. Free radicals derived from γ-radiolysis of water and AAPH thermolysis mediate oxidative crosslinking of eGFP involving Tyr-Tyr and Tyr-Cys bonds: the fluorescence of the protein is conserved only towards peroxyl radicals. Free Radic Biol Med 2020; 150:40-52. [PMID: 32081747 DOI: 10.1016/j.freeradbiomed.2020.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/29/2020] [Accepted: 02/08/2020] [Indexed: 10/25/2022]
Abstract
The enhanced green fluorescent protein (eGFP) is one of the most employed variants of fluorescent proteins. Nonetheless little is known about the oxidative modifications that this protein can undergo in the cellular milieu. The present work explored the consequences of the exposure of eGFP to free radicals derived from γ-radiolysis of water, and AAPH thermolysis. Results demonstrated that protein crosslinking was the major pathway of modification of eGFP towards these oxidants. As evidenced by HPLC-FLD and UPLC-MS, eGFP crosslinking would occur as consequence of a mixture of pathways including the recombination of two protein radicals, as well as secondary reactions between nucleophilic residues (e.g. lysine, Lys) with protein carbonyls. The first mechanism was supported by detection of dityrosine and cysteine-tyrosine bonds, whilst evidence of formation of protein carbonyls, along with Lys consumption, would suggest the formation and participation of Schiff bases in the crosslinking process. Despite of the degree of oxidative modifications elicited by peroxyl radicals (ROO•) generated from the thermolysis of AAPH, and free radicals generated from γ-radiolysis of water, that were evidenced at amino acidic level, only the highest dose of γ-irradiation (10 kGy) triggered significant changes in the secondary structure of eGFP. These results were accompanied by the complete loss of fluorescence arising from the chromophore unit of eGFP in γ-irradiation-treated samples, whereas it was conserved in ROO•-treated samples. These data have potential biological significance, as this fluorescent protein is widely employed to study interactions between cytosolic proteins; consequently, the formation of fluorescent eGFP dimers could act as artifacts in such experiments.
Collapse
Affiliation(s)
- Ricardo A Zamora
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile
| | - Eduardo Fuentes-Lemus
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile
| | - Pablo Barrias
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile
| | - Alejandra Herrera-Morande
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile; Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Francisco Mura
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile
| | - Victoria Guixé
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | | | - Tomás Rojas
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile
| | - Camilo López-Alarcón
- Departamento de Química Física, Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Paulina Aguirre
- Comisión Chilena de Energía Nuclear, Departamento de Tecnología Nucleares, Nueva Bilbao 12501, Santiago, 7600713, Chile
| | - Andrea Rivas-Aravena
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Lota 2465, Providencia, Santiago, 7510157, Chile.
| | - Alexis Aspée
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40 Correo 33, Santiago, Chile.
| |
Collapse
|