Crystal Structure and Substrate Recognition of Cellobionic Acid Phosphorylase, Which Plays a Key Role in Oxidative Cellulose Degradation by Microbes

ABSTRACT Complete cellulose degradation is the first step in the use of biomass as a source of renewable energy. To this end, the engineering of novel cellulase activity, the activity responsible for the hydrolysis of the β-1,4-glycosidic bonds in cellulose, is a topic of great interest. The high-resolution X-ray crystal structure of a multidomain endoglucanase from Clostridium cellulolyticum has been determined at a 1.6-Å resolution. The endoglucanase, Cel9G, is comprised of a family 9 catalytic domain attached to a family IIIc cellulose-binding domain. The two domains together form a flat platform onto which crystalline cellulose is suggested to bind and be fed into the active-site cleft for endolytic hydrolysis. To further dissect the structural basis of cellulose binding and hydrolysis, the structures of Cel9G in the presence of cellobiose, cellotriose, and a DP-10 thio-oligosaccharide inhibitor were resolved at resolutions of 1.7, 1.8, and 1.9 Å, respectively.

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Crystal structure and substrate recognition mechanism of Aspergillus oryzae isoprimeverose-producing enzyme

Journal of Structural Biology ◽

10.1016/j.jsb.2018.11.005 ◽

2019 ◽

Vol 205 (1) ◽

pp. 84-90 ◽

Cited By ~ 1

Author(s):

Tomohiko Matsuzawa ◽

Masahiro Watanabe ◽

Yusuke Nakamichi ◽

Zui Fujimoto ◽

Katsuro Yaoi

Keyword(s):

Crystal Structure ◽

Aspergillus Oryzae ◽

Substrate Recognition ◽

Recognition Mechanism

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The first crystal structure of human RNase 6 reveals a novel substrate-binding and cleavage site arrangement

Biochemical Journal ◽

10.1042/bcj20160245 ◽

2016 ◽

Vol 473 (11) ◽

pp. 1523-1536 ◽

Cited By ~ 13

Author(s):

Guillem Prats-Ejarque ◽

Javier Arranz-Trullén ◽

Jose A. Blanco ◽

David Pulido ◽

M. Victòria Nogués ◽

...

Keyword(s):

Crystal Structure ◽

Molecular Dynamics ◽

Kinetic Analysis ◽

Cleavage Site ◽

Substrate Recognition ◽

Site Directed Mutagenesis ◽

Directed Mutagenesis ◽

Cleavage Sites ◽

Human Rnase ◽

Dynamics Simulations

We describe the first human RNase 6 crystal structure in complex with sulfate anions. Kinetic analysis, site-directed mutagenesis and molecular dynamics simulations identified novel substrate recognition and cleavage sites.

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Crystal Structure of a GH3 β-Glucosidase from the Thermophilic Fungus Chaetomium thermophilum

International Journal of Molecular Sciences ◽

10.3390/ijms20235962 ◽

2019 ◽

Vol 20 (23) ◽

pp. 5962 ◽

Cited By ~ 2

Author(s):

Imran Mohsin ◽

Nirmal Poudel ◽

Duo-Chuan Li ◽

Anastassios C. Papageorgiou

Keyword(s):

Crystal Structure ◽

Elevated Temperatures ◽

Cellulose Degradation ◽

Thermophilic Fungus ◽

Biofuel Production ◽

Lignocellulose Degradation ◽

Thermophilic Fungi ◽

Biotechnological Applications ◽

Chaetomium Thermophilum ◽

Promising Source

Beta-glucosidases (β-glucosidases) have attracted considerable attention in recent years for use in various biotechnological applications. They are also essential enzymes for lignocellulose degradation in biofuel production. However, cost-effective biomass conversion requires the use of highly efficient enzymes. Thus, the search for new enzymes as better alternatives of the currently available enzyme preparations is highly important. Thermophilic fungi are nowadays considered as a promising source of enzymes with improved stability. Here, the crystal structure of a family GH3 β-glucosidase from the thermophilic fungus Chaetomium thermophilum (CtBGL) was determined at a resolution of 2.99 Å. The structure showed the three-domain architecture found in other β-glucosidases with variations in loops and linker regions. The active site catalytic residues in CtBGL were identified as Asp287 (nucleophile) and Glu517 (acid/base). Structural comparison of CtBGL with Protein Data Bank (PDB)-deposited structures revealed variations among glycosylated Asn residues. The enzyme displayed moderate glycosylation compared to other GH3 family β-glucosidases with similar structure. A new glycosylation site at position Asn504 was identified in CtBGL. Moreover, comparison with respect to several thermostability parameters suggested that glycosylation and charged residues involved in electrostatic interactions may contribute to the stability of the enzyme at elevated temperatures. The reported CtBGL structure provides additional insights into the family GH3 enzymes and could offer new ideas for further improvements in β-glucosidases for more efficient use in biotechnological applications regarding cellulose degradation.

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