8WX6

X-Ray crystal structure of glycoside hydrolase family 6 cellobiohydrolase from Phanerochaete chrysosporium PcCel6A C240S/C393S

Summary for 8WX6

• Entry DOI: 10.2210/pdb8wx6/pdb
• Related: 8WUP 8WW5 8WWT
• Descriptor: Glucanase (2 entities in total)
• Functional Keywords: glycoside hydrolase family 6, cellobiohydrolase, cellulase, catalytic domain, free cysteine, hydrolase
• Biological source: Phanerodontia chrysosporium
• Total number of polymer chains: 1
• Total formula weight: 38349.44

Authors

Yamaguchi, S.,Sunagawa, N.,Tachioka, M.,Igarashi, K. (deposition date: 2023-10-27, release date: 2024-09-04, Last modification date: 2024-10-09)

Primary citation

Yamaguchi, S.,Sunagawa, N.,Samejima, M.,Igarashi, K.
Thermotolerance Mechanism of Fungal GH6 Cellobiohydrolase. Part II. Structural Analysis of Thermotolerant Mutant from the Basidiomycete Phanerochaete chrysosporium.
J Appl Glycosci (1999), 71:63-72, 2024

PubMed Abstract: Glycoside hydrolase family 6 cellobiohydrolase (GH6 CBH) is a group of cellulases capable of hydrolyzing crystalline cellulose. However, the synergistic reaction of GH6 CBH with other cellulases is hindered by its relatively low thermotolerance. We previously obtained a thermotolerant double mutant, C240S/C393S, of GH6 CBH from the basidiomycete (Cel6A) by replacing the two free cysteine (Cys) residues, C240 and C393, with serine (Yamaguchi ., J Appl Glycosci. 2020; 67;79-86). In the accompanying paper (Part I; Yamaguchi ., J Appl Glycosci. 2024; 71: 55-62), we measured the temperature dependence of the activity and folding of C240S/C393S and its single mutants, C240S and C393S, and found that replacement of C393 was the major contributor to the increased thermotolerance of C240S/C393S. Here, in order to investigate the mechanism involved, we crystallized the wild-type and the mutant enzymes and compared their X-ray crystal structures. The overall structures of the wild-type and the three mutant enzymes were similar. However, C240S/C393S had the lowest relative -factor at both the N-terminal loop (residues 172-177) and the C-terminal loop (residues 390-425). This result suggests that reduced structural fluctuation of the substrate-enclosing loops, possibly due to stronger hydrogen bonding involving C393, could account for the increased thermotolerance of C240S/C393S.

PubMed: 38863950
DOI: 10.5458/jag.jag.JAG-2023_0018

Experimental method

X-RAY DIFFRACTION (0.99 Å)