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Title: The structure of the catalytic domain of a plant cellulose synthase and its assembly into dimers

Cellulose microfibrils are para-crystalline arrays of several dozen linear (1→4)-β-d-glucan chains synthesized at the surface of the cell membrane by large, multimeric complexes of synthase proteins. Recombinant catalytic domains of rice (Oryza sativa) CesA8 cellulose synthase form dimers reversibly as the fundamental scaffold units of architecture in the synthase complex. Specificity of binding to UDP and UDP-Glc indicates a properly folded protein, and binding kinetics indicate that each monomer independently synthesizes single glucan chains of cellulose, i.e., two chains per dimer pair. In contrast to structure modeling predictions, solution x-ray scattering studies demonstrate that the monomer is a two-domain, elongated structure, with the smaller domain coupling two monomers into a dimer. The catalytic core of the monomer is accommodated only near its center, with the plant-specific sequences occupying the small domain and an extension distal to the catalytic domain. This configuration is in stark contrast to the domain organization obtained in predicted structures of plant CesA. As a result, the arrangement of the catalytic domain within the CesA monomer and dimer provides a foundation for constructing structural models of the synthase complex and defining the relationship between the rosette structure and the cellulose microfibrils they synthesize.
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1] ;  [1] ;  [1] ;  [3] ;  [3] ;  [1] ;  [1]
  1. Purdue Univ., West Lafayette, IN (United States)
  2. Northeastern Univ., Boston, MA (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  4. DeltaG Technologies, San Diego, CA (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1040-4651
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Plant Cell
Additional Journal Information:
Journal Volume: 26; Journal Issue: 7; Related Information: Plant Cell; Journal ID: ISSN 1040-4651
American Society of Plant Biologists
Research Org:
NREL (National Renewable Energy Laboratory (NREL), Golden, CO (United States))
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
09 BIOMASS FUELS; 59 BASIC BIOLOGICAL SCIENCES plant cellulose synthase; dimer