3w24

Publication Abstract from PubMed

Xylanases are capable of decomposing xylans, the major components in plant cell wall, and releasing the constituent sugars for further applications. Because xylanase is widely used in various manufacturing processes, high specific activity and thermostability are desirable. Here, the wild-type and mutant (E146A and E251A) catalytic domain of xylanase from Thermoanaerobacterium saccharolyticum JW/SL-YS485 (TsXylA) were expressed in Escherichia coli and purified subsequently. The recombinant protein showed optimal temperature and pH of 75o C and 6.5, respectively, and it remained fully active even after heat treatment at 75o C for one hour. Furthermore, the crystal structures of apo-form wild-type TsXylA and the xylobiose-, xylotriose-, and xylotetraose-bound E146A and E251A mutants were solved by X-ray diffraction to high resolution (1.32-1.66 A). The protein forms a classic (beta/alpha)8 folding typical of GH10 xylanases. The ligands in substrate-binding groove as well as the interactions between sugars and active-site residues were clearly elucidated by analyzing the complex structures. According to the structural analyses, TsXylA utilizes a double displacement catalytic machinery to carry out the enzymatic reactions. In conclusion, TsXylA is effective under industrially favored conditions, and our findings provide fundamental knowledge which may contribute to further enhancement of the enzyme performance through molecular engineering. Proteins 2013. (c) 2013 Wiley Periodicals, Inc.

Structural and functional analyses of catalytic domain of GH10 xylanase from thermoanaerobacterium saccharolyticum JW/SL-YS485.,Han X, Gao J, Shang N, Huang CH, Ko TP, Chen CC, Chan HC, Cheng YS, Zhu Z, Wiegel J, Luo W, Guo RT, Ma Y Proteins. 2013 Mar 18. doi: 10.1002/prot.24286. PMID:23508990^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.