Characterization of a hyaluronic acid utilization locus and identification of hyaluronate lyases in human gut...

Hyaluronic acid (HA), a linear glycosaminoglycan, serves as a key structural constituent of extracellular matrices, participating in diverse biological processes across both normal physiological and pathological contexts. While the gut microbiota exerts a pivotal influence on HA utilization within the human body, current scientific literature indicates a limited understanding of the molecular mechanisms underlying this interaction. In this study, a gut bacterium Enterococcus faecalis F1221 has been isolated, which demonstrated the ability to degrade HA. Genome sequencing and functional annotation of E. faecalis F1221 disclosed its metabolic utilization of hyaluronic acid (HA)-specific gram-positive polysaccharide utilization loci (gpPUL). This genomic region harbored a novel gene cluster encoding a hyaluronidase EfHyl8, comprising a Carbohydrate-binding modules 70, a "β-sheet" fragment and a PL-8 catalytic domains. Truncated mutants of EfHyl8 all resulted in a decrease in their capacity to bind HA, which led to a decrease in their catalytic ability. EfHyl8 exhibited significant subcutaneous diffusion capacity and demonstrated favorable safety, making it suitable for application as a subcutaneous drug diffusion agent.