Initiation, Elongation, and Termination of Bacterial Cellulose Synthesis

John B. McManus, Hui Yang, Liza Wilson, James D. Kubicki, Ming Tien

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)2690-2698
Number of pages9
JournalACS Omega
Issue number3
StatePublished - Mar 31 2018

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)


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