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Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES

Cellulose is the most abundant biopolymer and a major reservoir of fixed carbon on earth. Comprehension of the elusive mechanism of its enzymatic degradation represents a fundamental problem at the interface of biology, biotechnology, and materials science. The interdependence of cellulose disintegr...

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Autores principales: Ganner, Thomas, Bubner, Patricia, Eibinger, Manuel, Mayrhofer, Claudia, Plank, Harald, Nidetzky, Bernd
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3527909/
https://www.ncbi.nlm.nih.gov/pubmed/23118223
http://dx.doi.org/10.1074/jbc.M112.419952
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author Ganner, Thomas
Bubner, Patricia
Eibinger, Manuel
Mayrhofer, Claudia
Plank, Harald
Nidetzky, Bernd
author_facet Ganner, Thomas
Bubner, Patricia
Eibinger, Manuel
Mayrhofer, Claudia
Plank, Harald
Nidetzky, Bernd
author_sort Ganner, Thomas
collection PubMed
description Cellulose is the most abundant biopolymer and a major reservoir of fixed carbon on earth. Comprehension of the elusive mechanism of its enzymatic degradation represents a fundamental problem at the interface of biology, biotechnology, and materials science. The interdependence of cellulose disintegration and hydrolysis and the synergistic interplay among cellulases is yet poorly understood. Here we report evidence from in situ atomic force microscopy (AFM) that delineates degradation of a polymorphic cellulose substrate as a dynamic cycle of alternating exposure and removal of crystalline fibers. Direct observation shows that chain-end-cleaving cellobiohydrolases (CBH I, CBH II) and an internally chain-cleaving endoglucanase (EG), the major components of cellulase systems, take on distinct roles: EG and CBH II make the cellulose surface accessible for CBH I by removing amorphous-unordered substrate areas, thus exposing otherwise embedded crystalline-ordered nanofibrils of the cellulose. Subsequently, these fibrils are degraded efficiently by CBH I, thereby uncovering new amorphous areas. Without prior action of EG and CBH II, CBH I was poorly active on the cellulosic substrate. This leads to the conclusion that synergism among cellulases is morphology-dependent and governed by the cooperativity between enzymes degrading amorphous regions and those targeting primarily crystalline regions. The surface-disrupting activity of cellulases therefore strongly depends on mesoscopic structural features of the substrate: size and packing of crystalline fibers are key determinants of the overall efficiency of cellulose degradation.
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spelling pubmed-35279092012-12-27 Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES Ganner, Thomas Bubner, Patricia Eibinger, Manuel Mayrhofer, Claudia Plank, Harald Nidetzky, Bernd J Biol Chem Enzymology Cellulose is the most abundant biopolymer and a major reservoir of fixed carbon on earth. Comprehension of the elusive mechanism of its enzymatic degradation represents a fundamental problem at the interface of biology, biotechnology, and materials science. The interdependence of cellulose disintegration and hydrolysis and the synergistic interplay among cellulases is yet poorly understood. Here we report evidence from in situ atomic force microscopy (AFM) that delineates degradation of a polymorphic cellulose substrate as a dynamic cycle of alternating exposure and removal of crystalline fibers. Direct observation shows that chain-end-cleaving cellobiohydrolases (CBH I, CBH II) and an internally chain-cleaving endoglucanase (EG), the major components of cellulase systems, take on distinct roles: EG and CBH II make the cellulose surface accessible for CBH I by removing amorphous-unordered substrate areas, thus exposing otherwise embedded crystalline-ordered nanofibrils of the cellulose. Subsequently, these fibrils are degraded efficiently by CBH I, thereby uncovering new amorphous areas. Without prior action of EG and CBH II, CBH I was poorly active on the cellulosic substrate. This leads to the conclusion that synergism among cellulases is morphology-dependent and governed by the cooperativity between enzymes degrading amorphous regions and those targeting primarily crystalline regions. The surface-disrupting activity of cellulases therefore strongly depends on mesoscopic structural features of the substrate: size and packing of crystalline fibers are key determinants of the overall efficiency of cellulose degradation. American Society for Biochemistry and Molecular Biology 2012-12-21 2012-11-01 /pmc/articles/PMC3527909/ /pubmed/23118223 http://dx.doi.org/10.1074/jbc.M112.419952 Text en © 2012 by The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice—Final version full access. Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) applies to Author Choice Articles
spellingShingle Enzymology
Ganner, Thomas
Bubner, Patricia
Eibinger, Manuel
Mayrhofer, Claudia
Plank, Harald
Nidetzky, Bernd
Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES
title Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES
title_full Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES
title_fullStr Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES
title_full_unstemmed Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES
title_short Dissecting and Reconstructing Synergism: IN SITU VISUALIZATION OF COOPERATIVITY AMONG CELLULASES
title_sort dissecting and reconstructing synergism: in situ visualization of cooperativity among cellulases
topic Enzymology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3527909/
https://www.ncbi.nlm.nih.gov/pubmed/23118223
http://dx.doi.org/10.1074/jbc.M112.419952
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