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Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii
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 spec...
Autores principales: | , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society of Microbiology
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4611034/ https://www.ncbi.nlm.nih.gov/pubmed/26419877 http://dx.doi.org/10.1128/mBio.01058-15 |
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author | Ze, Xiaolei Ben David, Yonit Laverde-Gomez, Jenny A. Dassa, Bareket Sheridan, Paul O. Duncan, Sylvia H. Louis, Petra Henrissat, Bernard Juge, Nathalie Koropatkin, Nicole M. Bayer, Edward A. Flint, Harry J. |
author_facet | Ze, Xiaolei Ben David, Yonit Laverde-Gomez, Jenny A. Dassa, Bareket Sheridan, Paul O. Duncan, Sylvia H. Louis, Petra Henrissat, Bernard Juge, Nathalie Koropatkin, Nicole M. Bayer, Edward A. Flint, Harry J. |
author_sort | Ze, Xiaolei |
collection | PubMed |
description | 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.” |
format | Online Article Text |
id | pubmed-4611034 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | American Society of Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-46110342015-10-25 Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii Ze, Xiaolei Ben David, Yonit Laverde-Gomez, Jenny A. Dassa, Bareket Sheridan, Paul O. Duncan, Sylvia H. Louis, Petra Henrissat, Bernard Juge, Nathalie Koropatkin, Nicole M. Bayer, Edward A. Flint, Harry J. mBio Research Article 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.” American Society of Microbiology 2015-09-29 /pmc/articles/PMC4611034/ /pubmed/26419877 http://dx.doi.org/10.1128/mBio.01058-15 Text en Copyright © 2015 Ze et al. http://creativecommons.org/licenses/by-nc-sa/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-ShareAlike 3.0 Unported license (http://creativecommons.org/licenses/by-nc-sa/3.0/) , which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Ze, Xiaolei Ben David, Yonit Laverde-Gomez, Jenny A. Dassa, Bareket Sheridan, Paul O. Duncan, Sylvia H. Louis, Petra Henrissat, Bernard Juge, Nathalie Koropatkin, Nicole M. Bayer, Edward A. Flint, Harry J. Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii |
title | Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii |
title_full | Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii |
title_fullStr | Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii |
title_full_unstemmed | Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii |
title_short | Unique Organization of Extracellular Amylases into Amylosomes in the Resistant Starch-Utilizing Human Colonic Firmicutes Bacterium Ruminococcus bromii |
title_sort | unique organization of extracellular amylases into amylosomes in the resistant starch-utilizing human colonic firmicutes bacterium ruminococcus bromii |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4611034/ https://www.ncbi.nlm.nih.gov/pubmed/26419877 http://dx.doi.org/10.1128/mBio.01058-15 |
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