Study on the framework of ATP energy cycle system in Escherichia coli.

The high mortality rate associated with single-use CRISPR-Cas9 in Escherichia coli limits its application. Recently, new CRISPR-based techniques for E.coli gene editing have emerged. Research aims to develop a system for rapid, marker-free, multi-site, and multi-copy genome editing in E.coli to advance synthetic biology. ATP, essential for energy in living organisms, plays a crucial role in various metabolic processes. To reduce the cost of ATP-requiring reactions, it is crucial to identify and efficiently express genes in ATP synthesis pathway. This study identified a single ppk gene (No.8) capable of completing the cyclic reaction. Using MUCICAT technology, the ppk gene (No.8) was inserted into various positions and copy numbers in the E.coli genome, resulting in different activity levels. The findings suggest that the difficulty of inserting the ppk gene (No.8) into the genome follows this order: IS186 < 8array < IS186 + 8array < IS1. A single genome insertion can mimic plasmid expression level. This study explores promoter competition and offers solutions, inspiring researchers in constructing the AMP-ATP cycle system in E.coli. KEY POINTS: • The single ppk gene (No.8) can regenerate the AMP-ATP cycle, crucial for ATP-dependent reactions. • Inserting the ppk gene (No.8) into the cr5 site of the E.coli genome achieves expression levels comparable to the pET29a plasmid. • The expression level of the ppk gene (No.8) is not significantly affected by its copy number in the E.coli genome.