ACKNOWLEDGMENTS We acknowledge support from BBSRC grant no. BB/L009951/1, from the Scottish government Food, Land and People program, and from the Society for Applied Microbiology. E.A.B. is supported by a grant (no. 1349/13) from the Israel Science Foundation (ISF), Jerusalem, Israel, and by a grant from the United States-Israel Binational Science Foundation (BSF). E.A.B. is the incumbent of the Maynard I. and Elaine Wishner Chair of Bio-organic Chemistry. Thanks are due to Fergus Nicol for proteomic analysis and to Auriane Bernard for enzyme assays on stationary-phase cultures. We also thank Julian Parkhill and Keith Turner (Wellcome Trust Sanger Institute, Cambridge, United Kingdom) for making the R. bromii L2-63 genome sequence available for analysis.Peer reviewedPublisher PD

Bayer, Edward A.

Dassa, Bareket

David, Ben

Duncan, Sylvia H

Flint, Harry J

Henrissat, Bernard

Juge, Natahlie

Koropatkin, Nicole M

Laverde Gomez, Jenny

Louis, Petra Gisela Helen

Sheridan, Paul O

Ze, Xiaolei

mBio

English

PubMed

Ben David, Yonit

Laverde-Gomez, Jenny A.

Sheridan, Paul O.

Duncan, Sylvia H.

Louis, Petra

Juge, Nathalie

Koropatkin, Nicole M.

Flint, Harry J.

Hal-Diderot

Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii

HAL AMU

HAL: Hyper Article en Ligne

ACKNOWLEDGMENTS We acknowledge support from BBSRC grant no. BB/L009951/1, from the Scottish government Food, Land and People program, and from the Society for Applied Microbiology. E.A.B. is supported by a grant (no. 1349/13) from the Israel Science Foundation (ISF), Jerusalem, Israel, and by a grant from the United States-Israel Binational Science Foundation (BSF). E.A.B. is the incumbent of the Maynard I. and Elaine Wishner Chair of Bio-organic Chemistry. Thanks are due to Fergus Nicol for proteomic analysis and to Auriane Bernard for enzyme assays on stationary-phase cultures. We also thank Julian Parkhill and Keith Turner (Wellcome Trust Sanger Institute, Cambridge, United Kingdom) for making the R. bromii L2-63 genome sequence available for analysis.Peer reviewe

Sheridan, Paul

Aberdeen University Research

ABSTRACT
          
            Ruminococcus bromii
            is a dominant member of the human gut microbiota that plays a key role in releasing energy from dietary starches that escape digestion by host enzymes via its exceptional activity against particulate “resistant” starches. Genomic analysis of
            R. bromii
            shows that it is highly specialized, with 15 of its 21 glycoside hydrolases belonging to one family (GH13). We found that amylase activity in
            R. bromii
            is expressed constitutively, with the activity seen during growth with fructose as an energy source being similar to that seen with starch as an energy source. Six GH13 amylases that carry signal peptides were detected by proteomic analysis in
            R. bromii
            cultures. Four of these enzymes are among 26
            R. bromii
            proteins predicted to carry dockerin modules, with one, Amy4, also carrying a cohesin module. Since cohesin-dockerin interactions are known to mediate the formation of protein complexes in cellulolytic ruminococci, the binding interactions of four cohesins and 11 dockerins from
            R. bromii
            were investigated after overexpressing them as recombinant fusion proteins. Dockerins possessed by the enzymes Amy4 and Amy9 are predicted to bind a cohesin present in protein scaffoldin 2 (Sca2), which resembles the ScaE cell wall-anchoring protein of a cellulolytic relative,
            R. flavefaciens
            . Further complexes are predicted between the dockerin-carrying amylases Amy4, Amy9, Amy10, and Amy12 and two other cohesin-carrying proteins, while Amy4 has the ability to autoaggregate, as its dockerin can recognize its own cohesin. This organization of starch-degrading enzymes is unprecedented and provides the first example of cohesin-dockerin interactions being involved in an amylolytic system, which we refer to as an “amylosome.”
          
          
            IMPORTANCE
            Fermentation of dietary nondigestible carbohydrates by the human colonic microbiota supplies much of the energy that supports microbial growth in the intestine. This activity has important consequences for health via modulation of microbiota composition and the physiological and nutritional effects of microbial metabolites, including the supply of energy to the host from short-chain fatty acids. Recent evidence indicates that certain human colonic bacteria play keystone roles in degrading nondigestible substrates, with the dominant but little-studied species
            Ruminococcus bromii
            displaying an exceptional ability to degrade dietary resistant starches (i.e., dietary starches that escape digestion by host enzymes in the upper gastrointestinal tract because of protection provided by other polymers, particle structure, retrogradation, or chemical cross-linking). In this report, we reveal the unique organization of the amylolytic enzyme system of
            R. bromii
            that involves cohesin-dockerin interactions between component proteins. While dockerins and cohesins are fundamental to the organization of cellulosomal enzyme systems of cellulolytic ruminococci, their contribution to organization of amylases has not previously been recognized and may help to explain the starch-degrading abilities of
            R. bromii
            .
          </jats:p

Xiaolei Ze

Yonit Ben David

Jenny A. Laverde-Gomez

Bareket Dassa

Paul O. Sheridan

Sylvia H. Duncan

Petra Louis

Bernard Henrissat

Nathalie Juge

Nicole M. Koropatkin

Edward A. Bayer

Harry J. Flint

Crossref

Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic
            <i>Firmicutes</i>
            Bacterium Ruminococcus bromii

http://creativecommons.org/licenses/by-nc-sa/3.0/

Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii

Abstract

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Aberdeen University Research

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