Homology between SARS CoV-2 and human proteins

Area of Science:

• Immunology
• Virology
• Molecular Biology

Background:

• The high contagiousness of SARS-CoV-2 suggests immune system evasion.
• Molecular mimicry, where viral proteins resemble host proteins, can deceive the immune system and potentially cause autoimmunity.

Purpose of the Study:

• To investigate potential molecular mimicry between SARS-CoV-2 proteins and human proteins.
• To identify specific viral protein segments homologous to human sequences that could be involved in immune evasion and autoimmunity.

Main Methods:

• Comparative proteomic analysis using the Uniprot database.
• Identification and localization of heptamer and octamer sequences in SARS-CoV-2 proteins (Spike, Envelope, and nonstructural proteins).
• Assessment of sequence homology between viral and human proteins.

Main Results:

• Over two dozen heptamer/octamer motifs homologous to human proteins were found in the SARS-CoV-2 Spike (S) protein, many projecting outwards.
• Homologous heptamer/octamer sequences were identified in the transmembrane domain of the Envelope (E) protein.
• Several nonstructural proteins (ORF3a, ORF7a, ORF7b, ORF8, ORF9b) were also implicated.

Conclusions:

• SARS-CoV-2 proteins, particularly S and E proteins, contain sequences that mimic human proteins, likely contributing to immune evasion and potential autoimmune responses.
• Specific viral proteins may be responsible for sensory dysfunctions, such as loss of smell and taste.