title: Broad phylogeny and functionality of cellulosomal components in the bovine rumen microbiome.
abstract: The cellulosome is an extracellular multi-enzyme complex that is considered one of the most efficient plant cell wall-degrading strategies devised by nature. Its unique modular architecture, achieved by high affinity and specific interaction between protein modules (cohesins and dockerins) enables formation of various enzyme combinations. Extensive research has been dedicated to the mechanistic nature of the cellulosome complex. Nevertheless, little is known regarding its distribution and abundance among microbes in natural plant fibre-rich environments. Here, we explored these questions in bovine rumen microbial communities, specialized in efficient degradation of lignocellulosic plant material. We bioinformatically screened for cellulosomal modules in this complex environment using a previously published ultra-deep fibre-adherent rumen metagenome. Intriguingly, a large portion of the functions of the dockerin-containing proteins were related to alternative biological processes, and not necessarily to the classic fibre degradation function. Our analysis was experimentally validated by characterizing specific interactions between selected cohesins and dockerins and revealed that cellulosome is a more generalized strategy used by diverse bacteria, some of which were not previously associated with cellulosome production. Remarkably, our results provide additional proof of similarity among rumen microbial communities worldwide. This study suggests a broader and widespread role for the cellulosomal machinery in nature.
authors.affiliation: Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Lizi
authors.initials: L
authors.lastname: Bensoussan
authors.affiliation: Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Sarah
authors.initials: S
authors.lastname: Moraïs
authors.affiliation: Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Bareket
authors.initials: B
authors.lastname: Dassa
authors.affiliation: The Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: Nir
authors.initials: N
authors.lastname: Friedman
authors.affiliation: Architecture et Fonction des Macromolécules Biologiques, UMR6098, Aix-Marseille University, CNRS UMR7257, Marseille, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Henrissat
authors.affiliation: Architecture et Fonction des Macromolécules Biologiques, UMR6098, Aix-Marseille University, CNRS UMR7257, Marseille, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Lombard
authors.affiliation: Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Bayer
authors.affiliation: The Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
authors.forename: Itzhak
authors.initials: I
authors.lastname: Mizrahi
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D044603:Cellulosomes / Q000201:enzymology* / Q000235:genetics; D000069196:Gastrointestinal Microbiome; D054892:Metagenome; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D012417:Rumen / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D009097:Multienzyme Complexes