Analyzing Signal Peptides for Secretory Production of Recombinant Diagnostic Antigen B8/1 from Echinococcus granulosus: An In silico Approach.

Recombinant AgB8/1 as the most evaluated antigen for serological diagnosis of Cystic Echinococcosis (CE) can provide early and accurate diagnosis for proper management and treatment of the disease. Thus, the secretory production of this recombinant protein is the main goal and the application of signal peptides at the N terminus of the desired protein can help to achieve this goal. The present study applied few bioinformatics tools to evaluate several signal peptides to offer the best candidate for extracellular production of AgB8/1 of Echinococcus granulosus in Escherichia coli. The sequences related to signal peptides were obtained from "Signal Peptide Website" and were checked by "UniProt". In addition, UniProt was employed to retrieve the sequence of AgB8/1. Then, the probable signal peptide sequences and their cleavage site locations were determined by SignalP 4.1 followed by evaluation of their physicochemical features, using ProtParam. The solubility of the target recombinant proteins was accessed by SOLpro. Finally, PRED-TAT and ProtCompB were implemented to predict protein secretion pathways and final destinations. Among the 39 candidate signal peptides, ENTC2_STAAU and ENTC1_STAAU are the best ones which are stable and soluble in connection with AgB8/1 and can secrete target protein through Sec pathway. The signal peptides recommended in this investigation are valuable for rational designing of secretory stable and soluble AgB8/1. Such information is useful for future experimental production of the mentioned antigen.