Ozone-induced damage of fibrinogen molecules: identification of oxidation sites by high-resolution mass spectrometry

Abstract

Fibrinogen is highly susceptible to oxidation compared to other plasma proteins. Fibrinogen oxidation damages its structure and affects the protein function. Ozone-induced oxidative modifications of the fibrinogen Aα, Bβ, and γ polypeptide chains upon addition of various amounts of the oxidiser were studied by mass spectrometry. Amino acid residues located on all three chains and main structural parts of the protein were revealed to be involved in oxidation. The αC-connector was shown to be most vulnerable to oxidation as compared to other structural parts while the E region turned out to be the most protected area of the protein. For the first time, it was established that numerous amino acid residues responsible for the conversion of fibrinogen to fibrin remain unaffected upon fibrinogen oxidation. The data obtained in this study indicate that none of the identified residues, which are considered crucial for the binding of both hole “a” and hole “b” to knob “A” and knob “B”, respectively, as well as those responsible for the thrombin binding to fibrinogen E region, have been subjected to chemical alterations under moderate oxidation. The data on fibrinogen oxidation acquired in the current study enable one to assume that some of the structural fibrinogen parts and easily oxidisable residues could be endowed with antioxidant properties. New findings presented here could be essential for the detection of adaptive molecular mechanisms capable of mitigating the detrimental action of reactive oxygen species (ROS) on the functioning of oxidatively damaged fibrinogen. Data are available via ProteomeXchange with identifier PXD012046.

Highlights

• Various oxidative modifications were detected in fibrinogen by mass spectrometry

• αC-connector has been shown to be most susceptible to oxidation

• E region proved to be least vulnerable to the action of the oxidising agent

• Some of the Met residues in the fibrinogen structure could operate as ROS scavengers

Keywords:

• Antioxidant structures
• fibrin selfassembly
• fibrinogen
• mass spectrometry
• oxidation
• oxidative post-translational modifications
• reactive oxygen species (ROS)
• structural adaptation

Acknowledgements

For analysing the fibrinogen samples, we used Instruments of the Core Facility of the Emanuel Institute of Biochemical Physics, Russian Academy of Sciences “New Materials and Technologies”.

The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE [57] partner repository with the dataset identifier PXD012046 and 10.6019/PXD012046.

The authors are grateful to A.V. Luzhin from the Institute of Gene Biology RAS for his help in automating the data processing.

Disclosure statement

The authors confirm that this article content has no conflicts of interest.

Additional information

Funding

The study was supported by RFBR project and № 18-04-01313-A. The part of research related to peptides and PTM identification by high-resolution mass spectrometry measurements was supported by the Russian Science Foundation № 16-14-00181.