Does the presence of ground state complex between a PR-10 protein and a sensitizer affect the mechanism of sensitized photo-oxidation?

Marta Ignasiak-Kciuk*, Karolina Nowicka-Bauer, Marta Grzechowiak, Tina Ravnsborg, Kamil Frąckowiak, Ole N. Jensen, Mariusz Jaskólski, Bronisław Marciniak

*Kontaktforfatter

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

27 Downloads (Pure)

Abstract

The mechanisms of one-electron protein oxidation are complicated and still not well-understood. In this work, we investigated the reaction of sensitized photo-oxidation using carboxybenzophenone (CB) as a sensitizer and a PR-10 protein (MtN13) as a quencher, which is intrinsically complicated due to the complex structure of the protein and multiple possibilities of CB attack. To predict and examine the possible reactions precisely, the 3D structure of the MtN13 protein was taken into account. Our crystallographic studies revealed a specific binding of the CB molecule in the protein's hydrophobic cavity, while mass spectrometry identified the amino acid residues (Met, Tyr, Asp and Phe) creating adducts with the sensitizer, thus indicating the sites of 3CB* quenching. In addition, protein aggregation was also observed. The detailed mechanisms of CB quenching by the MtN13 molecule were elucidated by an analysis of transient products by means of time-resolved spectroscopy. The investigation of the transient and stable products formed during the protein photo-oxidation was based on the data obtained from HPLC-MS analysis of model compounds, single amino acids and dipeptides. Our proposed mechanisms of sensitized protein photo-oxidation emphasize the role of a ground state complex between the protein and the sensitizer and indicate several new and specific products arising as a result of one-electron oxidation. Based on the analysis of the transient and stable products, we have demonstrated the influence of neighboring groups, especially in the case of Tyr oxidation, where the tyrosyl radical can be formed via a direct electron transfer from Tyr to CB* or via an intramolecular electron transfer from Tyr to Met radical cation Met > S+ or thiyl radical CysS from neighboring oxidized groups.

OriginalsprogEngelsk
TidsskriftFree Radical Biology and Medicine
Vol/bind198
Sider (fra-til)27-43
Antal sider17
ISSN0891-5849
DOI
StatusUdgivet - mar. 2023

Bibliografisk note

Funding Information:
This research was supported by the National Science Centre (NCN) of Poland [UMO-2017/27/B/ST4/00375]. The mass spectrometry platform used for the proteomics analysis of MtN13 was financed by a grant to the VILLUM Center for Bioanalytical Sciences (VILLUM Foundation grant no. 7292 to O.N.J.), by PRO-MS, Danish National Mass Spectrometry Platform for Functional Proteomics (grant no. 5072-00007B to O.N.J) and by Novo Nordisk Foundation (INTEGRA grant no. NNF20OC0061575 to O.N.J).Authors would like to thank dr. Gordon L. Hug from the Radiation Laboratory, Notre Dame University USA, for fruitful discussion on the mechanism of photo-oxidation of model compounds and protein. K.N.B. thanks A. Mickiewicz University to cover the short-term scientific visit at University of Southern Denmark by grant IDUB 006/07/POB3/0008.

Funding Information:
This research was supported by the National Science Centre (NCN) of Poland [ UMO-2017/27/B/ST4/00375 ]. The mass spectrometry platform used for the proteomics analysis of MtN13 was financed by a grant to the VILLUM Center for Bioanalytical Sciences (VILLUM Foundation grant no. 7292 to O.N.J.), by PRO-MS, Danish National Mass Spectrometry Platform for Functional Proteomics (grant no. 5072-00007B to O.N.J) and by Novo Nordisk Foundation (INTEGRA grant no. NNF20OC0061575 to O.N.J).

Publisher Copyright:
© 2023 The Authors

Fingeraftryk

Dyk ned i forskningsemnerne om 'Does the presence of ground state complex between a PR-10 protein and a sensitizer affect the mechanism of sensitized photo-oxidation?'. Sammen danner de et unikt fingeraftryk.

Citationsformater