<b>Distributional and evolutionary analyses of the </b><b><i>Escherichia coli</i></b><b> deubiquitinase ElaD through integrated bioinformatics analysis</b>

Pathogens employ a variety of effector proteins to modulate key host signaling pathways, thereby facilitating bacterial survival and enhancing pathogenicity. Despite lacking a complete ubiquitin system of their own, bacterial effector proteins frequently function as ubiquitin ligases or deubiquitinases (DUBs) to disrupt the eukaryotic ubiquitin machinery. DUBs have been found in a variety of bacteria, including ElaD, which has recently been recognized as a DUB in Escherichia coli (E. coli). However, the distributional and evolutionary analyses of ElaD in different E. coli remains largely unknown. In this study, we retrieved and analyzed the elaD gene sequences from the genomes of 530 E. coli strains. Then, molecular characterization of each strain was determined by bioinformatics methods. Phylogenetic tree was also constructed to analyze the evolutionary relationships between different ElaDs. Our findings demonstrate that the elaD gene was present in 66.60% (353/530) of both pathogenic and nonpathogenic E. coli strains. elaD gene is predominantly found in the O157, O26, O139 and O8 serotypes. The majority of elaD-positive strains belonged to phylogenetic groups B1, A, E and D, with the predominant sequence types being ST11, ST21, ST10, ST1 and ST69. ElaDs from different strains clustered in the phylogenetic tree in a correlation with O serotypes and phylogenetic groups. In addition, ElaDs of some branches showed premature translation termination. The widespread occurrence of the elaD gene among various E. coli strains suggests its potential significance in E. coli pathogenicity, although its precise functional role remains to be elucidated.