Japan Agency for Medical Research and Development (AMED)
JP22ama121003
日本
Japan Society for the Promotion of Science (JSPS)
24K10218
日本
Japan Society for the Promotion of Science (JSPS)
23K14519
日本
引用
ジャーナル: Nat Commun / 年: 2026 タイトル: Bacterial collagenase harnesses collagen geometry for processive cleavage. 著者: Hiroya Oki / Katsuki Takebe / Adjoa Bonsu / Kazunori Fujii / Ryo Masuda / Nicholas Henderson / Takehiko Mima / Takaki Koide / Mahmoud Moradi / Osamu Matsushita / Joshua Sakon / Kazuki Kawahara / 要旨: Collagen, the major structural protein in the animal extracellular matrix, forms a triple helix that resists proteolysis and requires specialised enzymes for degradation. Flesh-eating bacteria ...Collagen, the major structural protein in the animal extracellular matrix, forms a triple helix that resists proteolysis and requires specialised enzymes for degradation. Flesh-eating bacteria secrete collagenases that unwind the collagen triple helix and processively trim Gly-X-Y triplet repeats, yet the molecular basis of this process has remained obscure. Here, cryo-electron microscopy reveals how Hathewaya histolytica collagenase ColH engages its substrate and exploits the helix's architecture for catalysis. ColH encircles a single collagen triple helix in a closed-ring conformation and, through dynamic domain motions, dehydrates and destabilises it. The enzyme undergoes substrate-assisted twisting to adopt a rigid ratcheted conformation, in which one chain is bent into a tripeptide-long 'bight' and threaded into the active site for cleavage, while two uncut strands are partitioned to non-catalytic sites. Release of the bight appears to reset the enzyme, with the uncut strands serving as guiding tracks. Repeated cycling between dynamic and rigid states likely enables triplet-by-triplet translocation, allowing ColH to harness collagen's geometry for processive degradation. These findings reveal a bacterial strategy for collagen unwinding and cleavage distinct from that of mammalian collagenases, highlighting divergent evolutionary solutions for degrading one of nature's most intractable substrates.