PT - JOURNAL ARTICLE AU - Mei Zhao AU - Shenghu Zhou AU - Longtao Wu AU - Yu Deng TI - Machine learning-based promoter strength prediction derived from a fine-tuned synthetic promoter library in <em>Escherichia coli</em> AID - 10.1101/2020.06.25.170365 DP - 2020 Jan 01 TA - bioRxiv PG - 2020.06.25.170365 4099 - http://biorxiv.org/content/early/2020/06/26/2020.06.25.170365.short 4100 - http://biorxiv.org/content/early/2020/06/26/2020.06.25.170365.full AB - Promoters are one of the most critical regulatory elements controlling metabolic pathways. However, in recent years, researchers have simply perfected promoter strength, but ignored the relationship between the internal sequences and promoter strength. In this context, we constructed and characterized a mutant promoter library of Ptrc through dozens of mutation-construction-screening-characterization engineering cycles. After excluding invalid mutation sites, we established a synthetic promoter library, which consisted of 3665 different variants, displaying an intensity range of more than two orders of magnitude. The strongest variant was 1.52-fold stronger than a 1 mM isopropyl-β-D-thiogalactoside driven PT7 promoter. Our synthetic promoter library exhibited superior applicability when expressing different reporters, in both plasmids and the genome. Different machine learning models were built and optimized to explore relationships between the promoter sequences and transcriptional strength. Finally, our XgBoost model exhibited optimal performance, and we utilized this approach to precisely predict the strength of artificially designed promoter sequences. Our work provides a powerful platform that enables the predictable tuning of promoters to achieve the optimal transcriptional strength.Competing Interest StatementThe authors have declared no competing interest.