Enzymatic profiling of cellulosomal enzymes from the human gut bacterium, Ruminococcus champanellensis, reveals a fine-tuned system for cohesin-dockerin recognition.
Ruminococcus 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.
Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
Sarah
S
Moraïs
Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
Yonit
Y
Ben David
Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
Lizi
L
Bensoussan
Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK.
Sylvia H
SH
Duncan
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
Nicole M
NM
Koropatkin
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
Eric C
EC
Martens
Microbiology Group, Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK.
Harry J
HJ
Flint
Department of Biological Chemistry, The Weizmann Institute of Science, Rehovot, Israel.
Edward A
EA
Bayer
D001426:Bacterial Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D044603:Cellulosomes / Q000201:enzymology*; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D000069196:Gastrointestinal Microbiome / Q000502:physiology*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism; D045857:Ruminococcus / Q000201:enzymology* / Q000235:genetics; D000097722:Cohesins
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D002482:Cellulose; D002868:Chromosomal Proteins, Non-Histone; D006026:Glycoside Hydrolases; D009097:Multienzyme Complexes; D000097722:Cohesins; C072818:xyloglucan endo(1-4)-beta-D-glucanase; C109691:microcrystalline cellulose