5gyg

Crystal structure of ENZbleach xylanase T28C+T60C mutant with three N-teminal residue truncation

spinqualitylabelsall models 5gyg, resolution 1.74Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5gyg is a 2 chain structure with sequence from Termite gut metagenome. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.74Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed 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 kcat 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 degrees C for 1h and up to 3-fold increases at 60 degrees C. The most effective variants, XynTT and XynTTTE, exhibited 2-3-fold increases in bagasse hydrolysis at pH 9.0 and 60 degrees C compared to the wild-type enzyme. Overall, engineering arginines and phenylalanines for increased pKa 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. Structure-based protein engineering for thermostable and alkaliphilic enhancement of endo-beta-1,4-xylanase for applications in pulp bleaching.,Boonyapakron K, Jaruwat A, Liwnaree B, Nimchua T, Champreda V, Chitnumsub P J Biotechnol. 2017 Jul 31. pii: S0168-1656(17)31572-9. doi:, 10.1016/j.jbiotec.2017.07.035. PMID:28774672 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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