title: A Structural Study of CESA1 Catalytic Domain of Arabidopsis Cellulose Synthesis Complex: Evidence for CESA Trimers.
abstract: A cellulose synthesis complex with a "rosette" shape is responsible for synthesis of cellulose chains and their assembly into microfibrils within the cell walls of land plants and their charophyte algal progenitors. The number of cellulose synthase proteins in this large multisubunit transmembrane protein complex and the number of cellulose chains in a microfibril have been debated for many years. This work reports a low resolution structure of the catalytic domain of CESA1 from Arabidopsis (Arabidopsis thaliana; AtCESA1CatD) determined by small-angle scattering techniques and provides the first experimental evidence for the self-assembly of CESA into a stable trimer in solution. The catalytic domain was overexpressed in Escherichia coli, and using a two-step procedure, it was possible to isolate monomeric and trimeric forms of AtCESA1CatD. The conformation of monomeric and trimeric AtCESA1CatD proteins were studied using small-angle neutron scattering and small-angle x-ray scattering. A series of AtCESA1CatD trimer computational models were compared with the small-angle x-ray scattering trimer profile to explore the possible arrangement of the monomers in the trimers. Several candidate trimers were identified with monomers oriented such that the newly synthesized cellulose chains project toward the cell membrane. In these models, the class-specific region is found at the periphery of the complex, and the plant-conserved region forms the base of the trimer. This study strongly supports the "hexamer of trimers" model for the rosette cellulose synthesis complex that synthesizes an 18-chain cellulose microfibril as its fundamental product.
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Venu Gopal
authors.identifier: http://orcid.org/0000-0002-8894-1395
authors.initials: VG
authors.lastname: Vandavasi
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Daniel K
authors.identifier: http://orcid.org/0000-0001-8080-775X
authors.initials: DK
authors.lastname: Putnam
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Qiu
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Loukas
authors.initials: L
authors.lastname: Petridis
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: William T
authors.identifier: http://orcid.org/0000-0001-6456-2975
authors.initials: WT
authors.lastname: Heller
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: B Tracy
authors.initials: BT
authors.lastname: Nixon
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Candace H
authors.initials: CH
authors.lastname: Haigler
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Udaya
authors.initials: U
authors.lastname: Kalluri
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Leighton
authors.initials: L
authors.lastname: Coates
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Paul
authors.identifier: http://orcid.org/0000-0002-0247-3122
authors.initials: P
authors.lastname: Langan
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Jeremy C
authors.initials: JC
authors.lastname: Smith
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.).
authors.forename: Jens
authors.initials: J
authors.lastname: Meiler
authors.affiliation: Biology and Soft Matter Division (V.G.V., Q.Z., W.T.H., L.C., H.O.), BioSciences Division (L.P., U.K.), Center for Molecular Biophysics (L.P., J.C.S.), and Neutron Sciences Directorate (P.L.), Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831;Department of Biomedical Informatics (D.K.P., J.M.) and Department of Chemistry (J.M.), Vanderbilt University, Nashville, Tennessee 37232;Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania 16802 (B.T.N.);Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, North Carolina 27695 (C.H.H.); andDepartment of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996 (J.C.S., H.O.) oneillhm@ornl.gov.
authors.forename: Hugh
authors.identifier: http://orcid.org/0000-0003-2966-5527
authors.initials: H
authors.lastname: O'Neill
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D002482:Cellulose / Q000096:biosynthesis* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D029681:Arabidopsis Proteins; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; D002482:Cellulose; C110227:CESA1 protein, Arabidopsis; D005964:Glucosyltransferases