Genome Sequencing-Based Evolutionary Prediction of Glycan-Adhering Lectins and Experimental Evaluation of a Lectin (FimH) Inhibitor Using an Enterohemorrhagic Escherichia coli Strain Isolated in Korea

We analyzed the evolutionary characteristics of the predicted lectin-like adhesins to construct a lectin-glycan interaction network (LGI). A total of 20,603 assembled Esherichia. coli sequences were retrieved from NCBI, including 2,240 strains with Shiga toxin in their genome. A strain isolated from a Korean patient with diarrhea, EHEC NCCP14539, was also sequenced. The outer-membrane embedded proteins which could be adhesins were predicted from the annotated genes of E. coli strains. In addition, we performed a phylogenetic analysis using the fimH gene, a well-known adhesin of enterohemorrhagic E. coli (EHEC). Multiple sequence alignment of the 2,204 E. coli strains yielded an evolutionary tree. Multi-locus sequence typing-based phylogenetic analysis revealed that NCCP14539 is the ancestor of 70 EHEC strains. An experiment was conducted to find an FimH inhibitor using NCCP14539 strain. Using a T7 phage display method, FimH was selected as an adherent lectin from the GM1- and Gb3- attached lectins. Through simulation docking, we then confirmed that Gb3 has a stronger binding ability to FimH and inferred the binding site sequence. Thus, our results provide evidence that Gb3-derived peptides can act as novel agents to block FimH binding and prevent infection by EHEC.