ORF6
From Wikipedia, the free encyclopedia
| Betacoronavirus ORF6 protein | |||||||||
|---|---|---|---|---|---|---|---|---|---|
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| Identifiers | |||||||||
| Symbol | bCoV_NS6 | ||||||||
| Pfam | PF12133 | ||||||||
| InterPro | IPR022736 | ||||||||
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ORF6 is a gene that encodes a viral accessory protein in coronaviruses of the subgenus Sarbecovirus, including SARS-CoV and SARS-CoV-2. It is not present in MERS-CoV. It is thought to reduce the immune system response to viral infection through interferon antagonism.[2][3][4]
The ORF6 protein is fairly small, consisting of 63 amino acid residues in SARS-CoV[3] and 61 in SARS-CoV-2.[4] The ORF6 sequence is not well conserved, sharing only about 66% of the sequence between the two viruses.[5] However, from the emergence of SARS-CoV-2 in 2019 until 2025, the ORF6 sequence has only stably conserved one mutation: the last aspartate has mutated into a leucine (D61L).[6]
Its approximately 20-residue C-terminal tail is polar, extends into the cytosol. This region contains the conserved Methionine 58 needed for the interaction with RAE1 and NUP98[7] and signal sequences for protein trafficking.[2][3] The rest of the protein is amphipathic: the first 10 N-terminal residues act as a membrane anchor, while residues 11-45 form and amphiphilic alpha helix that associates with the membrane as an Integral monotopic membrane protein.[1]
