title: Computational and genetic evidence that different structural conformations of a non-catalytic region affect the function of plant cellulose synthase.
abstract: The β-1,4-glucan chains comprising cellulose are synthesized by cellulose synthases in the plasma membranes of diverse organisms including bacteria and plants. Understanding structure-function relationships in the plant enzymes involved in cellulose synthesis (CESAs) is important because cellulose is the most abundant component in the plant cell wall, a key renewable biomaterial. Here, we explored the structure and function of the region encompassing transmembrane helices (TMHs) 5 and 6 in CESA using computational and genetic tools. Ab initio computational structure prediction revealed novel bi-modal structural conformations of the region between TMH5 and 6 that may affect CESA function. Here we present our computational findings on this region in three CESAs of Arabidopsis thaliana (AtCESA1, 3, and 6), the Atcesa3(ixr1-2) mutant, and a novel missense mutation in AtCESA1. A newly engineered point mutation in AtCESA1 (Atcesa1(F954L) ) that altered the structural conformation in silico resulted in a protein that was not fully functional in the temperature-sensitive Atcesa1(rsw1-1) mutant at the restrictive temperature. The combination of computational and genetic results provides evidence that the ability of the TMH5-6 region to adopt specific structural conformations is important for CESA function.
authors.affiliation: Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Erin
authors.initials: E
authors.lastname: Slabaugh
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Latsavongsakda
authors.initials: L
authors.lastname: Sethaphong
authors.affiliation: Department of Biology, the Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Chaowen
authors.initials: C
authors.lastname: Xiao
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Amick
authors.affiliation: Department of Biology, the Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Charles T
authors.initials: CT
authors.lastname: Anderson
authors.affiliation: Department of Crop Science and Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA yara_yingling@ncsu.edu candace_haigler@ncsu.edu.
authors.forename: Candace H
authors.initials: CH
authors.lastname: Haigler
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695, USA yara_yingling@ncsu.edu candace_haigler@ncsu.edu.
authors.forename: Yaroslava G
authors.initials: YG
authors.lastname: Yingling
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D055162:Biocatalysis; D019295:Computational Biology; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
chemical_list: D029681:Arabidopsis Proteins; D050505:Mutant Proteins; D011993:Recombinant Fusion Proteins; D005964:Glucosyltransferases; C478648:cellulose synthase
keywords: CESA; Cellulose biosynthesis; genetic complementation; protein structural modelling; rsw1 mutant; transmembrane helix.