Molecular identification of hyaluronate lyase, not hyaluronidase, as an intrinsic hyaluronan-degrading enzyme in Clostridium perfringens strain ATCC 13124

Clostridium perfringens, an opportunistic pathogen, produces mu-toxin hyaluronidases including endo-β-N-acetylglucosaminidases (Nags) as a virulence invasion factor. To clarify an intrinsic factor for degradation of host extracellular hyaluronan, we focused on hyaluronate lyase (HysA), distinct from endo-β-N-acetylglucosaminidases. C. perfringens strain ATCC 13124 was found to assimilate host-derived extracellular mucosubstances, hyaluronan and mucin, which induced expression of the hyaluronan-related genetic cluster, including hyaluronate lyase gene (hysA), but repressed endo-β-N-acetylglucosaminidase genes. This genetic cluster is conserved in some strains of C. perfringens. The recombinant strain ATCC 13124 hyaluronate lyase HysA showed an hyaluronan-degrading activity through β-elimination reaction. The hyaluronan-degrading enzyme in the culture supernatant of strain ATCC 13124 exhibited the lyase activity and was identical to the recombinant hyaluronate lyase on the native-PAGE gel, followed by activity straining. These results demonstrated that the intrinsic hyaluronan-degrading enzyme of C. perfringens strain ATCC 13124 is hyaluronate lyase HysA, but not hyaluronidases NagH, NagJ, and NagK.