title: Promotion of crystalline cellulose degradation by expansins from Oryza sativa.
abstract: Enzymatic activities of Oryza sativa expansins, which were heterologously overexpressed in Escherichia coli , were analyzed. Results suggested that expansins promote degradation of cellulose by cellulase in a synergistic manner. Sustainable production of future biofuels is dependent on efficient saccharification of lignocelluloses. Expansins have received a lot of attention as proteins promoting biological degradation of cellulose using cellulase. The expansins are a class of plant cell wall proteins that induce cell wall loosening without hydrolysis. In this study, the expansins from Oryza sativa were classified using phylogenetic analysis and five proteins were selected for functional evaluation. At low cellulose loading, the cellulase in expansin mixtures was up to 2.4 times more active than in mixtures containing only cellulase, but at high cellulose loading the activity of cellulase in expansin mixtures and cellulase only mixtures did not differ. Furthermore, expansin activity was greater in cellulase mixtures compared with cellulase-deficient mixtures. Therefore, the expansins showed significant synergistic activity with cellulase. Expansin may play an important role in efficient saccharification of cellulose.
authors.affiliation: Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba-Ken, 278-8510, Japan, j0312705@ed.tus.ac.jp.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Seki
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Ryo
authors.initials: R
authors.lastname: Yoshimoto
authors.forename: Kenichi
authors.initials: K
authors.lastname: Aburai
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kanai
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Ruike
authors.forename: Kazuki
authors.initials: K
authors.lastname: Iwabata
authors.forename: Ryo
authors.initials: R
authors.lastname: Goitsuka
authors.forename: Fumio
authors.initials: F
authors.lastname: Sugawara
authors.forename: Masahiko
authors.initials: M
authors.lastname: Abe
authors.forename: Kengo
authors.initials: K
authors.lastname: Sakaguchi
mesh_terms: D002473:Cell Wall / Q000378:metabolism; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000737:chemistry / Q000378:metabolism*; D003460:Crystallization; D004591:Electrophoresis, Polyacrylamide Gel; D006868:Hydrolysis; D008954:Models, Biological; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D014961:X-Ray Diffraction
chemical_list: D010940:Plant Proteins; C095825:expansin protein, plant; D002482:Cellulose; D002480:Cellulase