Bottom-up amino acid sequencing of semi-domesticated Antheraea mylitta cocoonase enzyme and its in-silico evaluation [Mass Spectrometry Facility - Proteomics]

Cocoonase is a serine protease that has a principal role in the dissolution of sericin protein, which enables moth to escape out of the cocoon. This study presents the first report on amino acid sequence of naturally secreted Antheraea mylitta cocoonase (Daba Trivoltine ecorace). The present study revealed that, A. mylitta cocoonase comprised of 252 amino acids. The secondary structures were predicted using SOPMA and PROTEUS2 web server. The 3-D structure was modelled using trRosetta and validated using PROCHECK, ERRAT, and ProSA servers. Furthermore, physicochemical properties, gene ontology, molecular docking, protein-protein interactions, percentage protein coverage, and other aspects of cocoonase were studied. The analysis based on amino acid sequence and its composition revealed that cocoonase is a trypsin-like serine protease, having a theoretical pI of 8.87 and a molecular mass of 26.6 kDa. A negative GRAVY value indicated cocoonase to be non-polar. Based on the Ramachandran plot, 90.1% of the amino acid residues were found in the most preferred region. The entire quality factor of the predicted 3-D model by ERRAT2 was 96.72%. In addition, the model was also validated using ProSA web server with Z-Score − 7.29. Furthermore, the tblastn of amino acid sequence against the whole genome of A. mylitta showed 91.67% identity. Based on gene ontology study cocoonase is depicted to possess prospective biomedical and other industrial applications which can be utilized in near future.