Cellulose microfibril crystallinity is reduced by mutating C-terminal transmembrane region residues CESA1 A903V and CESA3 T942I of cellulose synthase

Darby M. Harris, Kendall Corbin, Tuo Wang, Ryan Gutierrez, Ana L. Bertolo, Carloalberto Petti, Detlef M. Smilgies, José Manuel Estevez, Dario Bonetta, Breeanna R. Urbanowicz, David W. Ehrhardt, Chris R. Somerville, Jocelyn K.C. Rose, Mei Hong, Seth DeBolt

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

120 Citas (Scopus)

Resumen

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 13C solidstate 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 A903Vand CESA3 T942I have modified microfibril structure in terms of crystallinity and suggest that in plants, as in bacteria, crystallization biophysically limits polymerization.

Idioma originalInglés
Páginas (desde-hasta)4098-4103
Número de páginas6
PublicaciónProceedings of the National Academy of Sciences of the United States of America
Volumen109
N.º11
DOI
EstadoPublicada - 13 mar 2012
Publicado de forma externa

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