Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 109, Issue 11, Pages 4098-4103Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.1200352109
Keywords
cell wall; polysaccharide; quinoxyphen
Categories
Funding
- National Science Foundation [NSF-IOS-0922947]
- NSF-REU
- Department of Energy DOE-FOA [10-0000368, DE-AC02-07CH11358, DOE-FGO2-03ER20133]
- National Institutes of Health/National Institute of General Medical Sciences via National Science Foundation [DMR-0936384]
- [PICT2010-0658]
- Direct For Biological Sciences [0922947] Funding Source: National Science Foundation
- Division Of Integrative Organismal Systems [0922947] Funding Source: National Science Foundation
Ask authors/readers for more resources
The mechanisms underlying the biosynthesis of cellulose in plants are complex and still poorly understood. A central question concerns the mechanism of microfibril structure and how this is linked to the catalytic polymerization action of cellulose synthase (CESA). Furthermore, it remains unclear whether modification of cellulose microfibril structure can be achieved genetically, which could be transformative in a bio-based economy. To explore these processes in planta, we developed a chemical genetic toolbox of pharmacological inhibitors and corresponding resistance-conferring point mutations in the C-terminal transmembrane domain region of CESA1(A903V) and CESA3(T942I) in Arabidopsis thaliana. Using C-13 solid-state nuclear magnetic resonance spectroscopy and X-ray diffraction, we show that the cellulose microfibrils displayed reduced width and an additional cellulose C4 peak indicative of a degree of crystallinity that is intermediate between the surface and interior glucans of wild type, suggesting a difference in glucan chain association during microfibril formation. Consistent with measurements of lower microfibril crystallinity, cellulose extracts from mutated CESA1(A903V) and CESA3(T942I) displayed greater saccharification efficiency than wild type. Using live-cell imaging to track fluorescently labeled CESA, we found that these mutants show increased CESA velocities in the plasma membrane, an indication of increased polymerization rate. Collectively, these data suggest that CESA1(A903V) and CESA3(T942I) have modified microfibril structure in terms of crystallinity and suggest that in plants, as in bacteria, crystallization biophysically limits polymerization.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available