Bioinformatics identification of an effective peptide signal for the expression of periplasmic human growth factor in E. coli

The human growth hormone is a single-chain polypeptide with a pivotal role in various biological processes. Although E. coli is considered a preferred host for producing human growth hormone, similar to many other eukaryotic proteins, the high expression of this protein in E. coli results in the accumulation of inclusion bodies. Periplasmic expression using signal peptides could be used to overcome the formation of inclusion body; still, the efficiency of each of the signal peptides in periplasmic transportation is varied and often protein specific. The present study aimed to use in silico analysis to identify an appropriate signal peptide for periplasmic expression of human growth hormone in E. coli. The amino acid sequences of ۹۱prokaryotic and eukaryotic signal peptides were collected from the signal peptide database, and each signal's characteristics and efficiency in connection with the target protein were analyzed by signalP۴.۱ server. The prediction of the secretory pathway and the cleavage position was determined by the signalP۵ server. Physicochemical properties, including molecular weight, instability index, Gravity and aliphatic index, were investigated by ProtParam software. The results of the present study showed that among all the signal peptides studied, five signal peptides ynfB, sfaS, lolA, glnH, and malE displayed high scores for periplasmic expression of Hgh in E. coli, respectively. In conclusion, the results indicated that in silico analysis could be used for the identification of suitable signal peptide for the periplasmic expression of proteins. Further laboratory studies can evaluate the accuracy of the results of the in silico analysis.

Keywords:

Soluble expression , Growth hormone , In silico , Escherichia coli