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Original- Cellulase
Structure:
Most fungal cellulases have a two-domain structure, with one catalytic domain and one cellulose binding domain, that are connected by a flexible linker. This structure is adapted for working on an insoluble substrate, and it allows the enzyme to diffuse two-dimensionally on a surface in a caterpillar-like fashion. However, there are also cellulases (mostly endoglucanases) that lack cellulose binding domains. These enzymes might have a swelling function.
Cellulase complexes:
In many bacteria, cellulases in-vivo are complex enzyme structures organized in supramolecular complexes, the cellulosomes. They contain roughly five different enzymatic subunits representing namely endocellulases, exocellulases, cellobiases, oxidative cellulases and cellulose phosphorylases wherein only endocellulases and cellobiases participate in the actual hydrolysis of the β(1→ 4) linkage.
Edit- Cellulase
Structure:
Most fungal cellulases have a two-domain structure, with one catalytic domain and one cellulose binding domain, that are connected by a flexible linker. This structure is adapted for working on an insoluble substrate, and it allows the enzyme to diffuse two-dimensionally on a surface in a caterpillar-like fashion. However, there are also cellulases (mostly endoglucanases) that lack cellulose binding domains.
Both binding of substrates and catalysis depend on the three-dimensional structure of the enzyme which arises as a consequence of the level of protein folding. The amino acid sequence and arrangement of their residues that occur within the active site, the position where the substrate binds, may influence factors like binding affinity of ligands, stabilization of substrates within the active site and catalysis. The substrate structure is complementary to the precise active site structure of enzyme. Changes in the position of residues may result in distortion of one or more of these interactions.[1] Additional factors like temperature, pH and metal ions influence the non-covalent interactions between enzyme structure.[2] The Thermotoga maritima species make cellulases consisting of 2 beta-sheets (protein structures) surrounding a central catalytic region which is the active-site.[3] The enzyme is categorised as an endoglucanase, which internally cleaves β-1,4 -glycosydic bonds in cellulose chains facilitating further degradation of the polymer. Different species in the same family as T. Maritima make cellulases with different structures.[4] Cellulases produced by the species Coprinopsis Cinerea consists of seven protein strands in the shape of an enclosed tunnel called a beta/alpha barrel.[5] These enzymes hydrolyse the substrate carboxymethyl cellulose. Binding of the substrate in the active site induces a change in conformation which allows degradation of the molecule.
Cellulase complexes:
In many bacteria, cellulases in-vivo are complex enzyme structures organized in supramolecular complexes, the cellulosomes. They can contain, but are not limited to, five different enzymatic subunits representing namely endocellulases, exocellulases, cellobiases, oxidative cellulases and cellulose phosphorylases wherein only endocellulases and cellobiases participate in the actual hydrolysis of the β(1→ 4) linkage. The number of sub-units making up cellulosomes can also determine the rate of enzyme activity.[6]
Rohet31 (talk) 06:45, 9 October 2017 (UTC) Rohet31 (talk) 06:47, 9 October 2017 (UTC) Rohet31 (talk) 06:23, 20 November 2017 (UTC) Rohet31 (talk) 06:28, 20 November 2017 (UTC)
- ^ Payne, Christina M.; Bomble, Yannick J.; Taylor, Courtney B.; McCabe, Clare; Himmel, Michael E.; Crowley, Michael F.; Beckham, Gregg T. (25 November 2011). "Multiple Functions of Aromatic-Carbohydrate Interactions in a Processive Cellulase Examined with Molecular Simulation". Journal of Biological Chemistry. 286 (47): 41028–41035. doi:10.1074/jbc.M111.297713. ISSN 0021-9258.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Lee, You-Jung; Kim, Bo-Kyung; Lee, Bo-Hwa; Jo, Kang-Ik; Lee, Nam-Kyu; Chung, Chung-Han; Lee, Young-Choon; Lee, Jin-Woo (1 January 2008). "Purification and characterization of cellulase produced by Bacillus amyoliquefaciens DL-3 utilizing rice hull". Bioresource Technology. pp. 378–386. doi:10.1016/j.biortech.2006.12.013.
- ^ Cheng, Ya-Shan; Ko, Tzu-Ping; Wu, Tzu-Hui; Ma, Yanhe; Huang, Chun-Hsiang; Lai, Hui-Lin; Wang, Andrew H.-J.; Liu, Je-Ruei; Guo, Rey-Ting (1 April 2011). "Crystal structure and substrate-binding mode of cellulase 12A from Thermotoga maritima". Proteins: Structure, Function, and Bioinformatics. 79 (4): 1193–1204. doi:10.1002/prot.22953. ISSN 1097-0134.
- ^ Cheng, Ya-Shan; Ko, Tzu-Ping; Wu, Tzu-Hui; Ma, Yanhe; Huang, Chun-Hsiang; Lai, Hui-Lin; Wang, Andrew H.-J.; Liu, Je-Ruei; Guo, Rey-Ting (1 April 2011). "Crystal structure and substrate-binding mode of cellulase 12A from Thermotoga maritima". Proteins: Structure, Function, and Bioinformatics. 79 (4): 1193–1204. doi:10.1002/prot.22953. ISSN 1097-0134.
- ^ Liu, Yuan; Yoshida, Makoto; Kurakata, Yuma; Miyazaki, Takatsugu; Igarashi, Kiyohiko; Samejima, Masahiro; Fukuda, Kiyoharu; Nishikawa, Atsushi; Tonozuka, Takashi (1 March 2010). "Crystal structure of a glycoside hydrolase family 6 enzyme, CcCel6C, a cellulase constitutively produced by Coprinopsis cinerea". FEBS Journal. 277 (6): 1532–1542. doi:10.1111/j.1742-4658.2010.07582.x. ISSN 1742-4658.
{{cite journal}}: no-break space character in|title=at position 120 (help) - ^ Tsai, Shen-Long; DaSilva, Nancy A.; Chen, Wilfred (18 January 2013). "Functional Display of Complex Cellulosomes on the Yeast Surface via Adaptive Assembly". ACS Synthetic Biology. 2 (1): 14–21. doi:10.1021/sb300047u.