title: Comparative Structural and Computational Analysis Supports Eighteen Cellulose Synthases in the Plant Cellulose Synthesis Complex.
abstract: A six-lobed membrane spanning cellulose synthesis complex (CSC) containing multiple cellulose synthase (CESA) glycosyltransferases mediates cellulose microfibril formation. The number of CESAs in the CSC has been debated for decades in light of changing estimates of the diameter of the smallest microfibril formed from the β-1,4 glucan chains synthesized by one CSC. We obtained more direct evidence through generating improved transmission electron microscopy (TEM) images and image averages of the rosette-type CSC, revealing the frequent triangularity and average cross-sectional area in the plasma membrane of its individual lobes. Trimeric oligomers of two alternative CESA computational models corresponded well with individual lobe geometry. A six-fold assembly of the trimeric computational oligomer had the lowest potential energy per monomer and was consistent with rosette CSC morphology. Negative stain TEM and image averaging showed the triangularity of a recombinant CESA cytosolic domain, consistent with previous modeling of its trimeric nature from small angle scattering (SAXS) data. Six trimeric SAXS models nearly filled the space below an average FF-TEM image of the rosette CSC. In summary, the multifaceted data support a rosette CSC with 18 CESAs that mediates the synthesis of a fundamental microfibril composed of 18 glucan chains.
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, PA 16802, USA.
authors.forename: B Tracy
authors.initials: BT
authors.lastname: Nixon
authors.affiliation: Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Katayoun
authors.initials: K
authors.lastname: Mansouri
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Abhishek
authors.initials: A
authors.lastname: Singh
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, PA 16802, USA.
authors.forename: Juan
authors.initials: J
authors.lastname: Du
authors.affiliation: Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Davis
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Jung-Goo
authors.initials: JG
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Slabaugh
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Venu Gopal
authors.initials: VG
authors.lastname: Vandavasi
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Hugh
authors.initials: H
authors.lastname: O'Neill
authors.affiliation: Department of Biology, Rhode Island College, Providence, RI 02908, USA.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Roberts
authors.affiliation: Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA.
authors.forename: Alison W
authors.initials: AW
authors.lastname: Roberts
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Yaroslava G
authors.initials: YG
authors.lastname: Yingling
authors.affiliation: Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Candace H
authors.initials: CH
authors.lastname: Haigler
mesh_terms: D002482:Cellulose / Q000096:biosynthesis / Q000737:chemistry*; D005964:Glucosyltransferases / Q000737:chemistry*; D008958:Models, Molecular; D010940:Plant Proteins / Q000737:chemistry*; D000072417:Protein Domains; D017510:Protein Folding; D020836:Protein Structure, Quaternary
chemical_list: D010940:Plant Proteins; D002482:Cellulose; D005964:Glucosyltransferases; C478648:cellulose synthase