Transposon mutant libraries of E. coli BW25113 parent strain and BW25113 ?dpaA (ldtF) strains were compared using transposon insertion sequencing. Two biological replicates of each of the libraries were sequenced and analysed.

Enterobacteriaceae members such as Escherichia coli covalently attach the abundant outer membrane-anchored lipoprotein Lpp Braun's lipoprotein) to tripeptides in peptidoglycan, mediated by the transpeptidases LdtA, LdtB and LdtC. LdtD and LdtE are members of the same family of LD-transpeptidases but they catalyse a different reaction, the formation of 3-3 cross-links in the peptidoglycan. The function of the sixth homologue in E. coli, LdtF (DpaA) remains unclear, although it has been shown to become essential in cells with inhibited LPS export to the outer membrane. To better understand the role of DpaA we performed genome-wide transposon insertion sequencing of the BW25113 dpaA mutant. Two libraries of transposon mutants were constructed by electroporation of a mini-Tn5 transposon into a ?dpaA strain, and the BW25113 parent strain as a control.