title: Enzymatic diversity of the Clostridium thermocellum cellulosome is crucial for the degradation of crystalline cellulose and plant biomass.
abstract: The cellulosome is a supramolecular multienzyme complex comprised of a wide variety of polysaccharide-degrading enzymes and scaffold proteins. The cellulosomal enzymes that bind to the scaffold proteins synergistically degrade crystalline cellulose. Here, we report in vitro reconstitution of the Clostridium thermocellum cellulosome from 40 cellulosomal components and the full-length scaffoldin protein that binds to nine enzyme molecules. These components were each synthesized using a wheat germ cell-free protein synthesis system and purified. Cellulosome complexes were reconstituted from 3, 12, 30, and 40 components based on their contents in the native cellulosome. The activity of the enzyme-saturated complex indicated that greater enzymatic variety generated more synergy for the degradation of crystalline cellulose and delignified rice straw. Surprisingly, a less complete enzyme complex displaying fewer than nine enzyme molecules was more efficient for the degradation of delignified rice straw than the enzyme-saturated complex, despite the fact that the enzyme-saturated complex exhibited maximum synergy for the degradation of crystalline cellulose. These results suggest that greater enzymatic diversity of the cellulosome is crucial for the degradation of crystalline cellulose and plant biomass, and that efficient degradation of different substrates by the cellulosome requires not only a different enzymatic composition, but also different cellulosome structures.
authors.affiliation: Department of Chemical Biology &Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Hirano
authors.affiliation: Department of Chemical Biology &Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaki
authors.affiliation: Department of Chemical Biology &Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nihei
authors.affiliation: Department of Chemical Biology &Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Hasegawa
authors.affiliation: Department of Chemical Biology &Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Suguru
authors.initials: S
authors.lastname: Shinoda
authors.affiliation: Department of Chemical Biology &Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Haruki
authors.affiliation: Department of Chemical Biology &Applied Chemistry, College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan.
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Hirano
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D018533:Biomass; D001711:Biotransformation; D002352:Carrier Proteins / Q000378:metabolism; D002480:Cellulase / Q000378:metabolism*; D044602:Cellulases / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism*; D048013:Acetivibrio thermocellus / Q000201:enzymology* / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism; D018547:Plant Stems / Q000378:metabolism; D014908:Triticum / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D009097:Multienzyme Complexes; C473132:cellulosome, Clostridium; C074074:cellulose binding protein A, Clostridium cellulovorans; D002482:Cellulose; D044602:Cellulases; D002480:Cellulase