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Ruminococcal cellulosome systems from rumen to human
Author(s) -
Ben David Yonit,
Dassa Bareket,
Borovok Ilya,
Lamed Raphael,
Koropatkin Nicole M.,
Martens Eric C.,
White Bryan A.,
BernalierDonadille Annick,
Duncan Sylvia H.,
Flint Harry J.,
Bayer Edward A.,
Moraïs Sarah
Publication year - 2015
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12868
Subject(s) - cellulosome , biology , cohesin , genome , computational biology , clostridium thermocellum , gene , genetics , rumen , bacteria , biochemistry , enzyme , cellulase , chromatin , fermentation
Summary A cellulolytic fiber‐degrading bacterium, R uminococcus champanellensis , was isolated from human faecal samples, and its genome was recently sequenced. Bioinformatic analysis of the R . champanellensis genome revealed numerous cohesin and dockerin modules, the basic elements of the cellulosome, and manual sequencing of partially sequenced genomic segments revealed two large tandem scaffoldin‐coding genes that form part of a gene cluster. Representative R . champanellensis dockerins were tested against putative cohesins, and the results revealed three different cohesin–dockerin binding profiles which implied two major types of cellulosome architectures: (i) an intricate cell‐bound system and (ii) a simplistic cell‐free system composed of a single cohesin‐containing scaffoldin. The cell‐bound system can adopt various enzymatic architectures, ranging from a single enzyme to a large enzymatic complex comprising up to 11 enzymes. The variety of cellulosomal components together with adaptor proteins may infer a very tight regulation of its components. The cellulosome system of the human gut bacterium R . champanellensis closely resembles that of the bovine rumen bacterium R uminococcus flavefaciens . The two species contain orthologous gene clusters comprising fundamental components of cellulosome architecture. Since R . champanellensis is the only human colonic bacterium known to degrade crystalline cellulose, it may thus represent a keystone species in the human gut.