title: The structure of the catalytic domain of a plant cellulose synthase and its assembly into dimers.
abstract: 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. 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.
authors.affiliation: Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054.
authors.forename: Anna T
authors.initials: AT
authors.lastname: Olek
authors.affiliation: Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054.
authors.forename: Catherine
authors.initials: C
authors.lastname: Rayon
authors.affiliation: Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115 Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115.
authors.forename: Lee
authors.initials: L
authors.lastname: Makowski
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971.
authors.forename: Hyung Rae
authors.initials: HR
authors.lastname: Kim
authors.affiliation: National Renewable Energy Laboratory, Biomolecular Science Group, Golden, Colorado 80401-3305.
authors.forename: Peter
authors.initials: P
authors.lastname: Ciesielski
authors.affiliation: DeltaG Technologies, San Diego, California 92122.
authors.forename: John
authors.initials: J
authors.lastname: Badger
authors.affiliation: Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907-2057.
authors.forename: Lake N
authors.initials: LN
authors.lastname: Paul
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971.
authors.forename: Subhangi
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971 Department of Computer Science, Purdue University, West Lafayette, Indiana 47907-2107.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kihara
authors.affiliation: National Renewable Energy Laboratory, Biomolecular Science Group, Golden, Colorado 80401-3305.
authors.forename: Michael
authors.initials: M
authors.lastname: Crowley
authors.affiliation: National Renewable Energy Laboratory, Biomolecular Science Group, Golden, Colorado 80401-3305.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Himmel
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971.
authors.forename: Jeffrey T
authors.initials: JT
authors.lastname: Bolin
authors.affiliation: Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971 Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907-2057 carpita@purdue.edu.
authors.forename: Nicholas C
authors.identifier: http://orcid.org/0000-0003-0770-314X
authors.initials: NC
authors.lastname: Carpita
mesh_terms: D020134:Catalytic Domain; D002462:Cell Membrane / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D055503:Protein Multimerization; D011994:Recombinant Proteins; D013379:Substrate Specificity
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D002482:Cellulose; D005964:Glucosyltransferases; C478648:cellulose synthase