5GY8

Crystal structure of ENZbleach xylanase T28C+T60C mutant

Summary for 5GY8

• Entry DOI: 10.2210/pdb5gy8/pdb
• Related: 5GV1 5GY9 5GYA 5GYB 5GYC 5GYE 5GYF 5GYG 5GYH 5GYI
• Descriptor: Endo-1,4-beta-xylanase (2 entities in total)
• Functional Keywords: endo-1, 4-beta-xylanase, gh11 xylanase, hydrolase
• Biological source: termite gut metagenome
• Total number of polymer chains: 1
• Total formula weight: 31561.80

Authors

Chitnumsub, P.,Jaruwat, A.,Boonyapakorn, K. (deposition date: 2016-09-22, release date: 2017-08-30, Last modification date: 2024-11-13)

Primary citation

Boonyapakron, K.,Jaruwat, A.,Liwnaree, B.,Nimchua, T.,Champreda, V.,Chitnumsub, P.
Structure-based protein engineering for thermostable and alkaliphilic enhancement of endo-beta-1,4-xylanase for applications in pulp bleaching
J. Biotechnol., 259:95-102, 2017

PubMed Abstract: In the pulp bleaching industry, enzymes with robust activity at high pH and temperatures are desirable for facilitating the pre-bleaching process with simplified processing and minimal use of chlorinated compounds. To engineer an enzyme for this purpose, we determined the crystal structure of the Xyn12.2 xylanase, a xylan-hydrolyzing enzyme derived from the termite gut symbiont metagenome, as the basis for structure-based protein engineering to improve Xyn12.2 stability in high heat and alkaline conditions. Engineered cysteine pairs that generated exterior disulfide bonds increased the k of Xyn12.2 variants and melting temperature at all tested conditions. These improvements led to up to 4.2-fold increases in catalytic efficiency at pH 9.0, 50°C for 1h and up to 3-fold increases at 60°C. The most effective variants, XynTT and XynTTTE, exhibited 2-3-fold increases in bagasse hydrolysis at pH 9.0 and 60°C compared to the wild-type enzyme. Overall, engineering arginines and phenylalanines for increased pK and hydrogen bonding improved enzyme catalytic efficiency at high stringency conditions. These modifications were the keys to enhancing thermostability and alkaliphilicity in our enzyme variants, with XynTT and XynTTTE being especially promising for their application to the pulp and paper industry.

PubMed: 28774672
DOI: 10.1016/j.jbiotec.2017.07.035

Experimental method

X-RAY DIFFRACTION (1.8 Å)