Background: Human fibrinogen, which plays a key role in plasma haemostasis, is a highly vulnerable target for oxidants. Fibrinogen undergoes posttranslational modifications that can potentially disrupt protein structure and function.
Methods: For the first time, by differential scanning calorimetry, dynamic and elastic light scattering and confocal laser scanning microscopy, the consequences of HOCl/-OCl-induced oxidation of fibrinogen on its thermal denaturation, molecular size distribution and fibrin clot network have been explored.
Results: Within a wide range of HOCl/-OCl concentrations (50-300 μM), the molecular size distribution remained unimodal; however, the average size of the hydrated molecules decreased. HOCl/-OCl-induced oxidation of fibrinogen resulted in the diminished thermal stability of regions D and E. As evidenced by elastic light scattering and confocal laser scanning microscopy, HOCl/-OCl caused the formation of abnormal fibrin with a decreased diameter of individual fibres.
Conclusions: The current results along with data from previous studies enable one to conclude that the effect of HOCl/-OCl-mediated oxidation on the thermal stability of region D is influenced directly by oxidative damage to the D region structure. Since the E region is not subjected to oxidative modification, its structural damage is likely to be mediated by the oxidation of other protein structures, in particular α-helical coiled-coils.
General significance: The experimental findings acquired in the current study could help to elucidate the consequences of oxidative stress in vivo on damage to the structure of fibrinogen/fibrin under the action of different ROS species.
Keywords: Confocal laser scanning microscopy; Differential scanning calorimetry; Dynamic and elastic light scattering; Fibrinogen/fibrin; Oxidation; Structure.
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