Lysozyme activity of the Ruminococcus champanellensis cellulosome

Sarah Moraïs, Darrell W. Cockburn, Yonit Ben-David, Nicole M. Koropatkin, Eric C. Martens, Sylvia H. Duncan, Harry J. Flint, Itzhak Mizrahi, Edward A. Bayer

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Abstract

Ruminococcus champanellensis is a keystone species in the human gut that produces an intricate cellulosome system of various architectures. A variety of cellulosomal enzymes have been identified, which exhibit a range of hydrolytic activities on lignocellulosic substrates. We describe herein a unique R. champanellensis scaffoldin, ScaK, which is expressed during growth on cellobiose and comprises a cohesin module and a family 25 glycoside hydrolase (GH25). The GH25 is non-autolytic and exhibits lysozyme-mediated lytic activity against several bacterial species. Despite the narrow acidic pH curve, the enzyme is active along a temperature range from 2 to 85°C and is stable at very high temperatures for extended incubation periods. The ScaK cohesin was shown to bind selectively to the dockerin of a monovalent scaffoldin (ScaG), thus enabling formation of a cell-free cellulosome, whereby ScaG interacts with a divalent scaffodin (ScaA) that bears the enzymes either directly or through additional monovalent scaffoldins (ScaC and ScaD). The ScaK cohesin also interacts with the dockerin of a protein comprising multiple Fn3 domains that can potentially promote adhesion to carbohydrates and the bacterial cell surface. A cell-free cellulosomal GH25 lysozyme may provide a bacterial strategy to both hydrolyze lignocellulose and repel eventual food competitors and/or cheaters.

Original languageEnglish (US)
Pages (from-to)5112-5122
Number of pages11
JournalEnvironmental microbiology
Volume18
Issue number12
DOIs
Publication statusPublished - Dec 1 2016

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All Science Journal Classification (ASJC) codes

  • Microbiology
  • Ecology, Evolution, Behavior and Systematics

Cite this

Moraïs, S., Cockburn, D. W., Ben-David, Y., Koropatkin, N. M., Martens, E. C., Duncan, S. H., ... Bayer, E. A. (2016). Lysozyme activity of the Ruminococcus champanellensis cellulosome. Environmental microbiology, 18(12), 5112-5122. https://doi.org/10.1111/1462-2920.13501