The rational modification of the secretion pathway: The bidirectional grinding strategy on signal peptide and SecA in Bacillus subtilis

The secretory (Sec) pathway is essential for protein translocation in Bacillus subtilis. In contrast to signal peptides (SPs), the key components of the Sec pathway lack excessive attention. Herein, based on the structural and mechanistic insights of SecA with SPs, the “Embedded-Model” was proposed, and the matching behavior was “grinded” to boost heterologous protein secretion efficiency. The binding structure of SecA with a SP was established and analyzed using comprehensive computational biology methods. An interaction-based grinding approach was explored for SP and SecA rational modification. The corresponding AprE exhibited 117.2% and 22.0% higher activities than those obtained using wild-type SP and SecA, respectively. Furthermore, a bidirectional grinding strategy was developed for both SPs and SecA. The AprE activity was therefore remarkably increased up to 349.6%. This study provides a novel and promising strategy for optimizing the secretion system and enhancing the secretory production of valuable proteins in B. subtilis.