Identification and characterization of sequence signatures in the Bacillus subtilis promoter P(ylb) for tuning promoter strength

OBJECTIVE: To thoroughly characterize the P(ylb) promoter and identify the elements that affect the promoter activity. RESULT: The sequences flanking the − 35 and − 10 box of the P(ylb) promoter were divided into six segments, and six random-scanning mutant promoter libraries fused to an enhanced green fluorescent protein EGFP were made and analyzed by flow cytometry. Our results showed that the four nucleotides flanking the − 35 box could mostly influence the promoter activity, and this influence was related to the GC content. The promoters mutated in these regions were successfully used for expressing the gene ophc2 encoding organophosphorus hydrolase (OPHC2) and the gene katA encoding catalase (KatA). CONCLUSION: Our work identified and characterized the sequence signatures of the P(ylb) promoter that could tune the promoter strength, providing further information for the potential application of this promoter. Meanwhile, the sequence signatures have the potential to be used for tuning gene expression in enzyme production, metabolic engineering, and synthetic biology. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10529-019-02749-4) contains supplementary material, which is available to authorized users.