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Enzymatic profiling of cellulosomal enzymes from the human gut bacterium, R uminococcus champanellensis , reveals a fine‐tuned system for cohesin‐dockerin recognition
Author(s) -
Moraïs Sarah,
David Yonit Ben,
Bensoussan Lizi,
Duncan Sylvia H.,
Koropatkin Nicole M.,
Martens Eric C.,
Flint Harry J.,
Bayer Edward A.
Publication year - 2016
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 - 10.1111/1462-2920.13047
Subject(s) - cellulosome , cohesin , biology , clostridium thermocellum , cellulase , glycoside hydrolase , biochemistry , enzyme , gene , chromatin
Summary R uminococcus champanellensis is considered a keystone species in the human gut that degrades microcrystalline cellulose efficiently and contains the genetic elements necessary for cellulosome production. The basic elements of its cellulosome architecture, mainly cohesin and dockerin modules from scaffoldins and enzyme‐borne dockerins, have been characterized recently. In this study, we cloned, expressed and characterized all of the glycoside hydrolases that contain a dockerin module. Among the 25 enzymes, 10 cellulases, 4 xylanases, 3 mannanases, 2 xyloglucanases, 2 arabinofuranosidases, 2 arabinanases and one β‐glucanase were assessed for their comparative enzymatic activity on their respective substrates. The dockerin specificities of the enzymes were examined by ELISA , and 80 positives out of 525 possible interactions were detected. Our analysis reveals a fine‐tuned system for cohesin–dockerin specificity and the importance of diversity among the cohesin–dockerin sequences. Our results imply that cohesin–dockerin pairs are not necessarily assembled at random among the same specificity types, as generally believed for other cellulosome‐producing bacteria, but reveal a more organized cellulosome architecture. Moreover, our results highlight the importance of the cellulosome paradigm for cellulose and hemicellulose degradation by R . champanellensis in the human gut.