Title: Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis

Abstract

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 aremore » 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.« less

Authors:

McManus, John B.; Yang, Hui; Wilson, Liza; Kubicki, James D.  ^[1];

• Search DOE PAGES for author "Kubicki, James D."
• Search DOE PAGES for ORCID "0000-0002-9277-9044"

Tien, Ming

• Search DOE PAGES for author "Tien, Ming"
• Search DOE PAGES for ORCID "0000-0003-0257-2347"

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+ Show Author Affiliations

1. Department of Geological Sciences, University of Texas at El Paso, El Paso, Texas 79968, United States

Publication Date:

Tue Mar 06 00:00:00 EST 2018

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Center for Lignocellulose Structure and Formation (CLSF); Pennsylvania State Univ., University Park, PA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1423927

Alternate Identifier(s):

OSTI ID: 1470257; OSTI ID: 1508757

Grant/Contract Number:  

SC0001090

Resource Type:

Published Article

Journal Name:

ACS Omega

Additional Journal Information:

Journal Name: ACS Omega Journal Volume: 3 Journal Issue: 3; Journal ID: ISSN 2470-1343

Publisher:

American Chemical Society (ACS)

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; biofuels (including algae and biomass); bio-inspired; membrane; carbon sequestration; materials and chemistry by design; synthesis (self-assembly); Biological and Medicinal chemistry; Enzyme kinetics; Theory