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Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis

[Image: see text] Cellulose is the major component of the plant cell wall and composed of β-linked glucose units. Use of cellulose is greatly impacted by its physical properties, which are dominated by the number of individual cellulose strand within each fiber and the average length of each strand....

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Autores principales: McManus, John B., Yang, Hui, Wilson, Liza, Kubicki, James D., Tien, Ming
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2018
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044951/
https://www.ncbi.nlm.nih.gov/pubmed/30023847
http://dx.doi.org/10.1021/acsomega.7b01808
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author McManus, John B.
Yang, Hui
Wilson, Liza
Kubicki, James D.
Tien, Ming
author_facet McManus, John B.
Yang, Hui
Wilson, Liza
Kubicki, James D.
Tien, Ming
author_sort McManus, John B.
collection PubMed
description [Image: see text] Cellulose is the major component of the plant cell wall and composed of β-linked glucose units. Use of cellulose is greatly impacted by its physical properties, which are dominated by the number of individual cellulose strand within each fiber and the average length of each strand. Our work described herein provides a complete mechanism for cellulose synthase accounting for its processivity and mechanism of initiation. Using ionic liquids and gel permeation chromatography, we obtain kinetic constants for initiation, elongation, and termination (release of the cellulose strand from the enzyme) for two bacterial cellulose synthases (Gluconacetobacter hansenii and Rhodobacter sphaeroides). Our results show that initiation of synthesis is primer-independent. After initiation, the enzyme undergoes multiple cycles of elongation until the strand is released. The rate of elongation is much faster than that of steady-state turnover. Elongation requires cyclic addition of glucose (from uridine diphosphate-glucose) and then strand translocation by one glucose unit. Translocations greater than one glucose unit result in termination requiring reinitiation. The rate of the strand release, relative to the rate of elongation, determines the processivity of the enzyme. This mechanism and the measured rate constants were supported by kinetic simulation. With the experimentally determined rate constants, we are able to simulate steady-state kinetics and mimic the size distribution of the product. Thus, our results provide for the first time a mechanism for cellulose synthase that accounts for initiation, elongation, and termination.
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spelling pubmed-60449512018-07-16 Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis McManus, John B. Yang, Hui Wilson, Liza Kubicki, James D. Tien, Ming ACS Omega [Image: see text] Cellulose is the major component of the plant cell wall and composed of β-linked glucose units. Use of cellulose is greatly impacted by its physical properties, which are dominated by the number of individual cellulose strand within each fiber and the average length of each strand. Our work described herein provides a complete mechanism for cellulose synthase accounting for its processivity and mechanism of initiation. Using ionic liquids and gel permeation chromatography, we obtain kinetic constants for initiation, elongation, and termination (release of the cellulose strand from the enzyme) for two bacterial cellulose synthases (Gluconacetobacter hansenii and Rhodobacter sphaeroides). Our results show that initiation of synthesis is primer-independent. After initiation, the enzyme undergoes multiple cycles of elongation until the strand is released. The rate of elongation is much faster than that of steady-state turnover. Elongation requires cyclic addition of glucose (from uridine diphosphate-glucose) and then strand translocation by one glucose unit. Translocations greater than one glucose unit result in termination requiring reinitiation. The rate of the strand release, relative to the rate of elongation, determines the processivity of the enzyme. This mechanism and the measured rate constants were supported by kinetic simulation. With the experimentally determined rate constants, we are able to simulate steady-state kinetics and mimic the size distribution of the product. Thus, our results provide for the first time a mechanism for cellulose synthase that accounts for initiation, elongation, and termination. American Chemical Society 2018-03-06 /pmc/articles/PMC6044951/ /pubmed/30023847 http://dx.doi.org/10.1021/acsomega.7b01808 Text en Copyright © 2018 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle McManus, John B.
Yang, Hui
Wilson, Liza
Kubicki, James D.
Tien, Ming
Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis
title Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis
title_full Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis
title_fullStr Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis
title_full_unstemmed Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis
title_short Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis
title_sort initiation, elongation, and termination of bacterial cellulose synthesis
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044951/
https://www.ncbi.nlm.nih.gov/pubmed/30023847
http://dx.doi.org/10.1021/acsomega.7b01808
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