Introduction

Our basic part is the signal peptide from the aprE gene, which was documented in detail and submitted as BBa_K1674000. It has been successfully used in the secretion of the mCherry reporter protein by B.subtilis, as can be seen in our results.

The Part

Bacillus subtilis is an industrially important bacterium which is commonly used as a host for the commercial production of proteins, especially enzymes such as proteases, amylases, and lipases. One of the major advantages of B. subtilis over many other bacteria is its ability to secrete large amounts of proteins into the growth medium, allowing efficient recovery of these protein products ¹.

aprE encodes for the main protease secreted by B.subtilis naturally, Subtilisin E. The signal peptide domain from aprE gene is part of the general secretion pathway (Sec pathway), where its role is to target pre-folded proteins to the membrane-bound protein translocation channel ^1,2.

The signal peptide from aprE can be used for secreting various proteins by fusing it to the N or C terminal of the desired protein. In previous research, this signal peptide has been proven to cause secretion of different proteins, such as cutinase, proinsulin, etc. ^{1,2, 3}

Our part can be used in the future for the secretion of various proteins. Therefore, it can help other groups, both in iGEM project and in the larger academic community, express proteins and extract them without the concern of degradation and inactivation, even when using aggressive lysis methods, such as a lysis buffer or sonication.