Article
Hypocrea jecorina (Trichoderma reesei) Cel7A as a molecular machine: A docking study.
Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011-2230, USA.
Proteins Structure Function and Bioinformatics (impact factor:
3.39).
10/2005;
60(4):598-605.
DOI:10.1002/prot.20547
Source: PubMed
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Citations (0)
- Cited In (3)
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Article: High speed atomic force microscopy visualizes processive movement of Trichoderma reesei cellobiohydrolase I on crystalline cellulose.
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ABSTRACT: Fungal cellobiohydrolases act at liquid-solid interfaces. They have the ability to hydrolyze cellulose chains of a crystalline substrate because of their two-domain structure, i.e. cellulose-binding domain and catalytic domain, and unique active site architecture. However, the details of the action of the two domains on crystalline cellulose are still unclear. Here, we present real time observations of Trichoderma reesei (Tr) cellobiohydrolase I (Cel7A) molecules sliding on crystalline cellulose, obtained with a high speed atomic force microscope. The average velocity of the sliding movement on crystalline cellulose was 3.5 nm/s, and interestingly, the catalytic domain without the cellulose-binding domain moved with a velocity similar to that of the intact TrCel7A enzyme. However, no sliding of a catalytically inactive enzyme (mutant E212Q) or a variant lacking tryptophan at the entrance of the active site tunnel (mutant W40A) could be detected. This indicates that, besides the hydrolysis of glycosidic bonds, the loading of a cellulose chain into the active site tunnel is also essential for the enzyme movement.Journal of Biological Chemistry 10/2009; 284(52):36186-90. · 4.77 Impact Factor -
Article: Targeted gene inactivation in Clostridium phytofermentans shows that cellulose degradation requires the family 9 hydrolase Cphy3367.
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ABSTRACT: Summary Microbial cellulose degradation is a central part of the global carbon cycle and has great potential for the development of inexpensive, carbon-neutral biofuels from non-food crops. Clostridium phytofermentans has a repertoire of 108 putative glycoside hydrolases to break down cellulose and hemicellulose into sugars, which this organism then ferments primarily to ethanol. An understanding of cellulose degradation at the molecular level requires learning the different roles of these hydrolases. In this study, we show that interspecific conjugation with Escherichia coli can be used to transfer a plasmid into C. phytofermentans that has a resistance marker, an origin of replication that can be selectively lost, and a designed group II intron for efficient, targeted chromosomal insertions without selection. We applied these methods to disrupt the cphy3367 gene, which encodes the sole family 9 glycoside hydrolase (GH9) in the C. phytofermentans genome. The GH9-deficient strain grew normally on some carbon sources such as glucose, but had lost the ability to degrade cellulose. Although C. phytofermentans upregulates the expression of numerous enzymes to break down cellulose, this process thus relies upon a single, key hydrolase, Cphy3367.Molecular Microbiology 09/2009; 74(6):1300-13. · 5.01 Impact Factor -
Article: Binding preferences, surface attachment, diffusivity, and orientation of a family 1 carbohydrate-binding module on cellulose.
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ABSTRACT: Cellulase enzymes often contain carbohydrate-binding modules (CBMs) for binding to cellulose. The mechanisms by which CBMs recognize specific surfaces of cellulose and aid in deconstruction are essential to understand cellulase action. The Family 1 CBM from the Trichoderma reesei Family 7 cellobiohydrolase, Cel7A, is known to selectively bind to hydrophobic surfaces of native cellulose. It is most commonly suggested that three aromatic residues identify the planar binding face of this CBM, but several recent studies have challenged this hypothesis. Here, we use molecular simulation to study the CBM binding orientation and affinity on hydrophilic and hydrophobic cellulose surfaces. Roughly 43 μs of molecular dynamics simulations were conducted, which enables statistically significant observations. We quantify the fractions of the CBMs that detach from crystal surfaces or diffuse to other surfaces, the diffusivity along the hydrophobic surface, and the overall orientation of the CBM on both hydrophobic and hydrophilic faces. The simulations demonstrate that there is a thermodynamic driving force for the Cel7A CBM to bind preferentially to the hydrophobic surface of cellulose relative to hydrophilic surfaces. In addition, the simulations demonstrate that the CBM can diffuse from hydrophilic surfaces to the hydrophobic surface, whereas the reverse transition is not observed. Lastly, our simulations suggest that the flat faces of Family 1 CBMs are the preferred binding surfaces. These results enhance our understanding of how Family 1 CBMs interact with and recognize specific cellulose surfaces and provide insights into the initial events of cellulase adsorption and diffusion on cellulose.Journal of Biological Chemistry 04/2012; 287(24):20603-12. · 4.77 Impact Factor
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Keywords
2 domains interact
catalytic domain
CD active site tunnel
cellulose chain
cellulose chains
cellulose-binding domain
crystalline cellulose surface
degrade crystalline cellulose
enzyme move
Enzyme-substrate interactions
forces
free chain end
glycosidic bond breakage
Hypocrea jecorina
interaction energies
molecular machine model
processive hydrolysis
Trichoderma reesei
