Membrane Cholesterol Modulates Oligomeric Status and Peptide-Membrane Interaction of Severe Acute Respiratory Syndrome Coronavirus Fusion Peptide

Abstract

The N-terminal fusion peptide (residues 770−788) of an S2 glycoprotein of the severe acute respiratory syndrome coronavirus (SARS-CoV), exposed upon receptor binding, is crucial for virus entry into the host cell. The fusion peptide alters the membrane organization and dynamics of the host membrane to facilitate membrane fusion. Generally, the effect of the fusion peptide on the membrane is sensitive to the lipid composition of target membranes. In the present work, we have utilized steady-state and time-resolved fluorescence spectroscopy in tandem with circular dichroism spectroscopy to elucidate the binding, oligomeric status, and secondary structure of the fusion peptide and its impact on the depthdependent membrane organization and dynamics. We have used depth-dependent fluorescence probes, 1,6-diphenyl-1,3,5-hexatriene (DPH) and its trimethylammonium derivative (TMA-DPH), to evaluate the effect of the peptide binding along the bilayer normal. We have exploited the energy transfer efficiency of tryptophan between TMA-DPH and DPH to determine the relative location of the solitary tryptophan present in the membrane-bound fusion peptide. We have further evaluated the effect of membrane cholesterol on the binding and organization of the peptide and the impact of peptide binding on the depth-dependent physical properties of the membrane at various cholesterol concentrations. Our results clearly demonstrate that the membrane cholesterol alters the oligomeric status of the membrane-bound peptide and the effect of peptide binding on the depth-dependent membrane organization and dynamics. The role of cholesterol is important, as the eukaryotic host cells contain a good amount of cholesterol that might be important for the entry of pathogenic viruses.

Computational Study of the Ion and Water Permeation and Transport Mechanisms of the SARS-CoV-2 Pentameric E Protein Channel

“…Different membrane components affect the permeability of the E protein pentamer ( Verdiá-Báguena et al, 2012 , 2013 ). In particular, cholesterol is very important for viral membrane fusion, vesicular transport of the E protein, and membrane protein self-assembly ( Tseng et al, 2010 ; Meher et al, 2019 ). In conclusion, the lipid membrane models must be carefully analyzed and interpreted in future studies; in particular, cholesterol must be incorporated into these models to clarify its role in determining the permeability of the pentameric E protein.…”

In Silico Discovery of Candidate Drugs against Covid-19

“…In addition, the results of pathway analysis showed that the genes were enriched in the cholesterol biosynthesis. The role of cholesterol is essential as the entry of pathogenic viruses into the cell is favoured by the presence of cholesterol on the eukaryotic host cells, as discussed before [45].…”

Lipidomics Issues on Human Positive ssRNA Virus Infection: An Update

“…However, a recent study shows that the cholesterol action is likely to involve a direct influence on the oligomeric state of the fusion peptide after insertion into the host cell membrane, as well as on the effects of the fusion peptide on the membrane reorganization and dynamics [43]. In another recent study, a new lipid-label-free methodology was used to measure the kinetics of influenza virus infection [44]. According to the results of this study, cholesterol is able to augment the efficiency of membrane fusion in a receptor binding-independent manner.…”