In silico analysis of signal peptides for secretory production of a-amylase in Bacillus subtilis

Abstract

α-Amylases are important commercial enzymes and have a broad application in industrial processes and medicine. Gram-positive bacteria such as Bacillus subtilis are possible host organisms for α-amylases secretory production. Secretion of α-amylases to the culture medium versus intracellular production has several advantages such as prevention of inclusion bodies accumulation, higher product stability and solubility. Signal peptides are considered as one of the most essential elements for successful secretory synthesis of the recombinant proteins. Therefore, by the selection of an efficient signal peptide, secretion of the recombinant protein can be enhanced. The goal of this investigation was the in silico evaluation of several peptides to find the most suitable leader peptides for secretory production of α-amylase in B. subtilis. In present work, 30 signal peptides were selected, and numerous online servers such as SignalP, ProtParam, SOLpro, PRED-TAT and ProtComp was used for investigation of suitable signal peptides. According to in silico predictions all other signal peptides connected to α-amylase were stable and soluble except PPBD_BACSU. PPBD_BACSU because of having D-score below cut-off could not be recognized as a suitable signal peptide for α-amylase. Computational analysis identified QOX2_BACSU may direct protein into transmembrane location and was ignored. All 28 remained were predicted as secretory signal peptides which can excrete protein out of the bacteria. The signal peptides recommended by the present study are valuable for rational designing of secretory soluble α-amylase. Although, such information can be useful for future experimental production of these mentioned secretory proteins.