@conference{
author = "Simović, Ana and Bićanin, Maša and Radomirović, Mirjana Ž. and Aćimovič, Jelena and Mitić, Dragana and Stanić-Vučinić, Dragana and Ćirković-Veličković, Tanja",
year = "2023",
abstract = "The emergence of the novel coronavirus SARS-CoV-2 has attracted the attention of the whole scientific community. However, as there are significant concerns regarding the effectiveness of vaccines and drugs against novel SARS-CoV-2 variants, naturally derived broad-spectrum of antivirals seems to be precious adjuvant agents to assist in combat against this disease. Phycocyanobilin (PCB) is an open-chain tetrapyrrole chromophore of phycocyanin (PC), chromoprotein derived from Spirullina, with strong anti-oxidative action. The role of disulfide bonds and thiol-disulfide balance in RBD is considered to play a significant role in the binding of S protein to ACE2 receptor. In RBD, in contrast to C480–C488 disulfide, which is thermodynamically stable, C379–C432 and C391–C525 disulfides are in dynamic equilibrium with their thiol states and, thus these two pairs of disulfides are more sensitive to changes in redox poise. Our study aimed to investigate impact of PCB on disulfide balance of RBD by redox proteomics and to investigate structural changes in the protein exposed to PCB. The effect of PCB on RBD secondary structures was examined by far-UV CD spectroscopy after titration of RBD with increasing concentrations of PCB. The presence of PCB had a pronounced effect on the spectral shape. RBD is dominantly composed of random coils and β-sheets. In the presence of PCB a slight increase of α-helical and random coils content, while the content of β-sheets and β-turns is decreased. Mapping redox-active disulfides and reactive cysteines in recombinant SARS-CoV-2 RBD was done using redox proteomics on both recombinant RBD and PCB-exposed RBD. A mass shift caused by alkylation of free Cys residues was detected on three Cys residues demonstrating disulfides C379–C432 and 432-391 to be semi-stable in both RBD and PCB-exposed RBD. Our results demonstrate that RBD exposed to PCB undergo structural changes but does not change the redox state of its critical semi-stable disulfides.
Acknowledgment: The authors acknowledge support of the special Research Fund (BOF) of Ghent University (grant number 01N01718) and the Ministry of Science, Innovation and technological development of the Republic of Serbia (Contract number: 451-03-68/2023-14/200168).",
publisher = "Italian Proteomics Association",
journal = "ItPA HPS and SePA XVII International Congress: Proteomics and Metabolomics towards Global Health, November 29th – December 1st, 2023, Roma, Italy",
title = "Redox status of critical disulfides of SARS-CoV-2 receptor-binding-domain exposed to bioactive chomophore phycocyanobilin",
pages = "63-63",
url = "https://hdl.handle.net/21.15107/rcub_cherry_6418"
}
