解淀粉芽孢杆菌I型信号肽酶与信号肽的相互作用

Interaction between type I signal peptidase and signal peptides in Bacillus amyloliquefaciens

摘要:

【目的】基于I型信号肽酶在分泌系统中的重要作用，探究信号肽酶与信号肽之间的作用关系，指导氨肽酶在解淀粉芽孢杆菌中的分泌表达优化。【方法】对解淀粉芽孢杆菌TCCC 19030的内源性信号肽酶和信号肽进行筛选，采用相对荧光强度、酶活力等表征手段进行分析，同时采用分子对接技术探究信号肽酶和信号肽的相互作用关系。【结果】信号肽YolC融合氨肽酶的胞外酶活力最高，达到11 847.67 U/mL。过表达信号肽酶SipW后，氨肽酶的酶活力提高到16 261 U/mL。分子对接结果显示，信号肽YolC与信号肽酶SipW结合自由能最低，为−4.4 kcal/mol。【结论】信号肽优化与信号肽酶过表达可有效提高氨肽酶的分泌表达，其中信号肽酶与信号肽的结合能是影响目的蛋白分泌量的关键因素之一。

Abstract:

[Objective] Based on the critical role of type I signal peptidase in the secretion system, this study explores the interaction between signal peptidase and signal peptides to guide the optimization of aminopeptidase secretion expression in Bacillus amyloliquefaciens. [Methods] The endogenous signal peptidase and signal peptide of Bacillus amyloliquefaciens TCCC 19030 were examined using relative fluorescence intensity and enzyme activity for analysis, and molecular docking to study their interaction. [Results] The signal peptide YolC fused with aminopeptidase exhibited the highest extracellular enzyme activity, reaching 11 847.67 U/mL. Overexpression of the signal peptidase SipW increased aminopeptidase activity to 16 261 U/mL. Molecular docking results also showed that YolC had the lowest binding free energy with SipW, at −4.4 kcal/mol. [Conclusion] Optimization of signal peptides and overexpression of signal peptidase can effectively enhance the secretion of aminopeptidase. The binding energy between signal peptidase and signal peptide is a key factor influencing the secretion levels of the target protein.