Determination of single nucleotide variants in Escherichia coli DH5α by using short-read sequencing

Abstract

Escherichia coli DH5a is a common laboratory strain that provides an important platform for routine use in cloning and synthetic biology applications. Many synthetic circuits have been constructed and successfully expressed in E. coli DH5a; however, its genome sequence has not been determined yet. Here, we determined E. coli DH5a genome sequence and identified genetic mutations that affect its phenotypic functions by using short-read sequencing. The sequencing results clearly described the genotypes of E. coli DH5a, which aid in further studies using the strain. Additionally, we observed 105 single nucleotide variants (SNVs), 83% of which were detected in protein-coding regions compared to the parental strain E. coli DH1. Interestingly, 23% of the protein-coding regions have mutations in their amino acid residues, whose biological functions were categorized into two-component systems, peptidoglycan biosynthesis and lipopolysaccharide biosynthesis. These results underscore the advantages of E. coli DH5a, which tolerates the components of transformation buffer and expresses foreign plasmids efficiently. Moreover, these SNVs were also observed in the commercially available strain. These data provide the genetic information of E. coli DH5a for its future application in metabolic engineering and synthetic biology.