A serpin from the gut bacterium Bifidobacterium longum inhibits eukaryotic elastase-like serine proteases

Dmitri Ivanov, Celine Emonet, Francis Foata, Michael Affolter, Michelle Delley, Makda Fisseha, Stephanie Blum-Sperisen, Sunil Kochhar, Fabrizio Arigoni

Research output: Contribution to journalArticlepeer-review

139 Scopus citations


Serpins form a large class of protease inhibitors involved in regulation of a wide spectrum of physiological processes. Recently identified prokaryotic members of this protein family may provide a key to the evolutionary origins of the unique serpin fold and the associated inhibitory mechanism. We performed a biochemical characterization of a serpin from Bifidobacterium longum, ananaerobic Gram-positive bacterium that naturally colonizes human gastrointestinal tract. The B. longum serpin was shown to efficiently inhibit eukaryotic elastase-like proteases with a stoichiometry of inhibition close to 1. Porcine pancreatic elastase and human neutrophil elastase were inhibited with the second order association constants of 4.7 × 104 M -1 s-1 and 2.1 × 104 M-1 s-1, respectively. The B. longum serpin is expected to be active in the gastrointestinal tract, because incubation of the purified recombinant serpin with mouse feces produces a stable covalent serpin-protease adduct readily detectable by SDS-PAGE. Bifidobacteria may encounter both pancreatic elastase and neutrophil elastase in their natural habitat and protection against exogenous proteolysis may play an important role in the interaction between these commensal bacteria and their host.

Original languageEnglish (US)
Pages (from-to)17246-17252
Number of pages7
JournalJournal of Biological Chemistry
Issue number25
StatePublished - Jun 23 2006
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Cell Biology


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