Towards a Yersinia pestis lipid A recreated in an Escherichia coli scaffold genome

Synthetic biology and genome engineering capabilities have facilitated the utilization of bacteria for a myriad of applications, ranging from medical treatments to biomanufacturing of complex molecules. The bacterial outer membrane, specifically the lipopolysaccharide (LPS), plays an integral role in the physiology, pathogenesis, and serves as a main target of existing detection assays for Gram-negative bacteria. Here we use CRISPR/Cas9 recombineering to insert Yersinia pestis lipid A biosynthesis genes into the genome of an Escherichia coli strain expressing the lipid IV_a subunit. We successfully inserted three genes: kdsD, lpxM, and lpxP into the E. coli genome and demonstrated their expression via reverse transcription PCR (RT-PCR). Despite observing expression of these genes, analytical characterization of the engineered strain's lipid A structure via MALDI-TOF mass spectrometry indicated that the Y. pestis lipid A was not recapitulated in the E. coli background. As synthetic biology and genome engineering technologies advance, novel applications and utilities for the detection and treatments of dangerous pathogens like Yersinia pestis will continue to be developed.