Results

Through mass spectrometry, we identified peptides that cover 44.91% of the α-subunit protein(697 aa) sequence, indicating that the protein has been expressed and identified to a certain extent in the expression system. Specifically, we observed 124 peptide-spectrum matches (PSMs), which provide a solid foundation for the identification of the α-subunit protein. In addition, there are 28 unique peptides matched to the α-subunit protein, and these unique peptides are a sign of identifying a certain protein, and their identification further strengthens our confidence in the identification results of the α-subunit protein. The theoretical molecular weight of the α-subunit protein is 77.9 kDa, and the protein matching score Score Sequest HT is 311.53, this high score indicates a high credibility of protein matching.

The expression and mass spectrometry analysis results of the β-subunit protein(322 aa) in the E.Coli expression system are also encouraging. Mass spectrometry analysis shows that the identified peptides cover 63.66% of the β-subunit protein sequence, and this high coverage indicates that the expression and identification efficiency of the β-subunit protein in the expression system are relatively high. In addition, we recorded 146 peptide-spectrum matches (PSMs), which further confirm the successful identification of the β-subunit protein. It is worth noting that there are 15 unique peptides matched to the β-subunit protein, and the identification of these unique peptides provides strong evidence for the identification of the β-subunit protein. The theoretical molecular weight of the β-subunit protein is 35 kDa, and the protein matching score Score Sequest HT is 381.62, this high score also indicates a high credibility of protein matching.

The molecular weight of β-subunit protein is relatively smaller, but its identification coverage is higher than α-subunit, which may indicate its expression efficiency in the expression system.